How to Become a Copywriter at a Marketing Agency: What to Write, How to Build a Portfolio and Pass a Test Assignment

In short

A copywriter at a marketing agency understands who the text is for and why, and that’s what sets them apart from “someone who writes nicely.” They know how to turn a business task into words that make a client book, order, or subscribe. Below is how to become a copywriter at an agency with no experience: what exactly you’ll have to write, how “pretty” text differs from text that sells (with three rewrites), how to research a brand before working on it, where the limits of AI usefulness are, how to build a portfolio of 8 pieces, pass a test assignment and an interview, and then grow into a content lead. Written from the practice of MOVE Agency, where copywriters work with dozens of brands in HoReCa, retail, healthcare, and energy.

What an agency copywriter actually writes

The MOVE copywriter job posting lists the duties briefly: website copy, social media posts, ads and blog articles, creative concepts for brands, SEO articles, editing and proofreading, collaboration with designers and the marketing team. Behind each item is a separate format with its own rules.

The key difference between an agency and working for a single brand: today you write about coffee, tomorrow about dentistry, the day after about electricity. That’s why an agency values the ability to switch quickly between audiences and speak each one’s language more than “author’s style.” How this looks in practice is shown in the ONDO case: a utility service started speaking to customers in plain language, and content views grew 44x and reach 162x.

”Pretty” and “sells”: the difference

Beginners most often write the way they were taught to write school essays: epithets, metaphors, generalizations. Business needs something else: after reading, a person should understand what’s being offered, why it’s for them, and what to do next. Three universal checks for any text:

1. Can you picture it? If a phrase can’t be seen in your head as an image, it’s empty.
2. Can it be disputed? “Best quality” can’t be verified, so it’s not an argument. “Ready in 12 minutes” can be verified, so it works.
3. Could anyone else say this? If a competitor could copy the sentence unchanged, you haven’t said anything about the brand yet.

Below are three typical rewrites. The examples are illustrative, not from real projects.

Example 1. A coffee shop, a post about a new seasonal drink.

• Before: “Cozy atmosphere, aromatic coffee, and the unforgettable taste of autumn await you at our coffee shop!”
• After: “Pumpkin raf (a creamy espresso drink) with oat milk. We brew it until November 15, then not again until next fall. Come before 11:00: a second cup for whoever’s with you is half price.”

What changed: words that mean nothing disappeared, and the product, a deadline, and a reason to come in the morning appeared.

Example 2. A dental clinic, homepage.

• Before: “We take care of your smile with love and professionalism.”
• After: “We treat cavities in a single visit, no pain. First consultation and X-ray are free. Book online at a time that works for you.”

What changed: a specific service, a specific benefit, the patient’s main fear was addressed, and a call to action was added.

Example 3. An auto shop, ad copy.

• Before: “Professional car repair of any complexity at affordable prices.”
• After: “Suspension diagnostics in 40 minutes, while you drink coffee in the waiting area. We tell you what to do now and what can wait.”

What changed: a universal promise was replaced with a visit scenario and honesty as the argument.

Notice that none of the rewrites introduced “creativity” in the usual sense. Facts appeared. Creativity at an agency begins after the facts have been gathered.

Research before the text: 80% of the work

A good text is 80% the work done before opening the document. The minimum set before any task:

• The brief and a talk with the project manager. Besides “what to write,” also “why,” “for whom,” and “what the person should do after.”
• The product from the inside. Menu, price list, service page, reviews. If possible, visit the place or use the service yourself.
• The customers’ language. Comments under posts, questions in DMs, reviews on maps. People write the wording themselves that later converts.
• Competitors. What they promise, which words are worn out in the niche, and what nobody says.
• Objections. Why a person might not buy: too expensive, too far, don’t trust it, not right now. Each objection becomes a future paragraph of the text.

At an agency, this research is often already in the strategy or content calendar. How it’s built for restaurants was covered in content calendar for a restaurant. A copywriter who reads the strategy before the first post saves themselves and the team weeks of edits.

Tone of voice: writing in someone else’s voice

At an agency, you don’t have your own style. Or rather, you do, but it doesn’t matter: what matters is the brand’s voice. Tone of voice is usually fixed in a brand book or strategy and describes three things: how the brand addresses a person, which words it uses and avoids, and how serious or ironic it is.

A practical way to “get into the voice”: before writing, reread the brand’s last 10 posts that the client considers successful, and note recurring constructions, forms of address, and joke topics. Then write the text and check: if this post appeared without a logo, would followers recognize the brand? If not, your voice is showing through instead of the brand’s.

A special situation arises in collaborations, when two brands with different voices have to coexist in one text. How to combine them without losing recognizability is covered in a separate piece on brand collaborations.

AI as a drafting tool and its limits

A copywriter who doesn’t use AI loses on speed. A copywriter who submits generated text without edits loses on quality and the client’s trust. Neither extreme survives at an agency.

Where AI genuinely helps:

• putting together the structure of an article or script from a brief;
• generating 20 headline options, of which you’ll pick and rewrite two;
• turning a long client document into a short list of facts;
• checking text for repetition and overly long sentences;
• quickly adapting one text into several formats.

Where AI doesn’t work or does harm:

• Facts. Models confidently invent prices, addresses, dish ingredients, and service specs. Every fact has to be checked with the client.
• Brand voice. By default, AI writes “average” text full of worn-out phrases. That’s exactly what we fixed in the examples above.
• Local context. Jokes, city events, seasonality, the specifics of the Ukrainian audience.
• Responsibility. You’re the one responsible for what’s published, not the tool.

A simple rule: AI writes the draft, the person writes the text. If you’re asked in an interview how you use AI, an honest answer with specific examples will be a plus. “I don’t use it on principle” or “I write everything with it” will be a minus.

An 8-piece portfolio people open to the end

Building a portfolio without experience is a straightforward task, nothing to worry about. You don’t need clients for it: take real brands and write for them as if they’d hired you. An optimal set of 8 pieces:

1. A website homepage for a local business: headline, subheadline, three benefit blocks, a call to action.
2. A series of three social media posts for one brand with a consistent voice.
3. A Reels script up to 30 seconds long with a hook, development, and payoff.
4. Three ad copy variations for one offer aimed at different audience segments.
5. A newsletter email with a subject line, preheader, and one action.
6. An SEO article of 1,000 to 1,500 words targeting a specific query, with a heading structure.
7. A rewrite: someone else’s weak text and your version, with an explanation of what you changed and why.
8. A short creative campaign concept: an idea in one paragraph and how it breaks down into posts, video, and ads.

Add three lines to each piece: what the task was, who the text was for, why you made those particular decisions. That comment is exactly what sets a copywriter apart from someone who just types words. Put it all in one link that opens on a phone without registration.

Test assignment and interview: what they’re actually checking

An agency’s test assignment is usually short: a post or two, a small piece of website copy, or a script. What’s checked is the logic of your decisions, length is secondary:

• Whether you read the brief all the way through and asked clarifying questions if something was missing.
• Whether the text has specifics instead of a set of general words.
• Whether the format is followed: length, structure, call to action.
• Whether you submitted on time. A test assignment deadline works as a rehearsal for a real deadline.
• Whether you can explain every decision: why this headline, why this order of arguments.

In an interview, expect questions about process, not inspiration: how you research a product, how you react to edits, what you do when a client asks to “make it more creative” without explanation. Prepare answers using examples from your portfolio. And ask questions back: how the text approval process works, who edits, what feedback looks like. This shows you’re thinking about the job, not just the job posting.

Where to grow: from copywriter to content lead

A copywriter’s first year at an agency goes toward formats and speed. After that, growth follows three paths.

Content lead or editor. You stop writing everything yourself and start being responsible for the content of several brands: planning, assigning tasks to writers, maintaining quality and voice. This requires learning to explain edits so the writer gets it right on their own next time.

Strategist. A copywriter who researches the audience well naturally moves toward strategy: positioning, content pillars, communication platform. It’s the same process, just at the brand level instead of a single text. At MOVE, strategy exists as a separate service, and strong copywriters take part in it.

Creative direction. Campaign concepts, big ideas that later break down into dozens of texts and videos. This is the path for those who think in stories rather than formats.

The one trait that unites all three paths: you think “what should happen after someone reads this” before “what to write.” That’s exactly what makes social media management work aimed at sales instead of likes. The result of this kind of thinking is visible in the Avtomotiv case, where content moved beyond “repairs and services” and brought 34% more service inquiries. And for those who want to build marketing knowledge systematically, the Move School course is a good fit.

6 mistakes beginner copywriters make

1. Writing without research. Text based on a two-line brief always comes back for revision. Ask more before you start.
2. Confusing tone with voice. Your favorite style doesn’t matter if the brand speaks differently. The brand’s voice comes first, then your craft within it.
3. General words instead of facts. Readers skip over “quality,” “professional,” “unique” as empty space. Replace each one with a fact or cut it.
4. Submitting an AI draft as a finished text. It’s visible from the first paragraph. To the client, the editor, and the readers.
5. Taking edits personally. An edit carries information about the brand and audience that you didn’t have. Find out why, note it, don’t repeat it.
6. An “everything goes” portfolio. Forty posts with no task or result say less than eight pieces with explanations.

If reading this made you recognize your own texts in the rewrites and want to fix them, that’s already the right reflex. Check out MOVE’s job openings: even if the copywriter position is closed right now, send your 8-piece portfolio, and we’ll open it first when a spot appears.