Letter Writing Etiquette: The Dos and Don'ts

Most letter-writing rules come down to one question: does this match the relationship? A job application and a note to an old friend follow different conventions, and mixing them up is what makes a letter land wrong. Here are the dos and don'ts that actually matter, for both formal and informal letters.

Formal vs. informal letters

A formal letter sticks to a set structure — it's for job applications, official complaints, and business inquiries. You include both addresses, open with "Dear," and close with a formal sign-off. No emoji, no slang. Our full guide to writing a letter covers the shape in detail; the essentials are an official greeting, a short intro, the detail split across paragraphs, a wrap-up, and a signature.

An informal letter is the opposite. These are your letters to friends and family, where personal news, congratulations, and a casual invitation all fit. The structure is loose and the tone is relaxed.

The parts of a formal letter

Address and greeting

This is where the letter either starts right or stumbles. Put your address at the top left, skip a line, then the date. Below that, add the recipient's address. Open with "Dear" plus their title and last name; if you don't have a name, a title or "To Whom It May Concern" works.

Example:

123 Main Street
City, State, ZIP Code
[Date]

456 Another Street
City, State, ZIP Code

Dear Dr. Smith,

Body paragraphs

The body carries your message. Open with why you're writing, keep it short. Use a paragraph or two for the detail — the who, what, and why. Then close by recapping, asking for what you need, and saying thanks.

Example:

I am writing to apply for the Senior Project Manager position at XYZ Corporation. With over ten years of experience in project management, I believe I am ideally prepared for this role.

In my previous position at ABC Company, I managed several high-profile projects, wrapping them up on time and under budget...

Thank you for considering my application. I look forward to the opportunity to dive deeper into my experience.

Closing and signature

Finish cleanly. Sign off with "Sincerely," "Best regards," or "Yours faithfully," then sign your name in blue or black ink with your typed name, title, and contact details below.

Example:

Sincerely,
[Your handwritten signature]
John Doe
Senior Project Manager

Get those right and you've got a solid professional letter. If you'd rather start from a draft, try our free formal letter generator.

The don'ts

In formal letters

• Don't get casual: skip "Hey there," slang, and contractions like "gonna" or "can't."
• Don't add personal anecdotes — save the weekend stories for a different letter.
• Don't use emoji; even a friendly smiley reads as unprofessional here.
• Don't wing the format: include both addresses, place the date consistently, and keep alignment and spacing tidy.
• Don't bury your purpose or pad the letter — get to the point without writing a novel.

In informal letters

• Don't skip the basics: even a casual letter needs your address and the date.
• Don't assume shared context — not every reader gets your inside jokes.
• Don't drift between topics, and don't leave a request unclear just because the tone is relaxed.

In any letter

• Don't skip the proofread. Typos, grammar slips, and the wrong name all undercut you.
• Don't sound like a template. Personalise the message — form letters are obvious.
• Don't ignore the reader's perspective: write what they need to know, not just what you want to say.
• Don't get the mechanics wrong: readable font, blue or black ink, a signature, and proper paper for formal letters.
• Don't make demands or air grievances without offering a way forward.

Quick reference: dos and don'ts

None of this is complicated, but it isn't a free-for-all either. When you're unsure, ask whether you'd want to receive the letter you just wrote. If the answer is no, it's worth another pass.