Posted on 13 July 2026

How to Set Up a Professional Email Signature: The Complete Guide

Your email signature is the most-repeated piece of branding your business owns. A single employee sending 40 emails a day puts your logo, name and call-to-action in front of thousands of people a year — yet most signatures are an afterthought pasted together in the email client and quietly broken on half the devices that receive them.

This guide walks through the whole process the right way: what a professional signature should contain, how to design and size it so it survives real inboxes, how to build one without touching code, and how to install it in every major email client. It links out to the detailed, client-by-client instructions in our documentation so you always have the exact steps for your setup.

What a professional email signature should include

A signature is not a business card — restraint reads as confidence. Include the essentials and cut everything else:

• Full name and job title — who you are and why you’re emailing.
• Company name and logo — the brand anchor, kept small and sharp.
• One primary phone number — not three; choose the one you actually answer.
• Website and key link — your site, or a single relevant call-to-action.
• Legal details where required — for UK limited companies this is a legal obligation, covered below.

Skip inspirational quotes, a wall of social icons, and “please consider the environment” lines. If everything is emphasised, nothing is.

Design principles that survive real inboxes

Email clients are not web browsers. Outlook renders with Word’s engine, Gmail strips much of your CSS, and dark mode can invert your colours. Design defensively:

• Keep it around 300–600px wide so it doesn’t overflow on mobile.
• Use web-safe fonts — custom fonts won’t load; Arial, Helvetica and Georgia always will.
• Size images correctly — export logos at 2× the display size for retina screens, then set explicit width/height so layouts don’t jump.
• Never send images as attachments — hosted images keep your signature light and stop it triggering the paperclip icon.

Want the deeper version? Our Signature School breaks down layout, colour and imagery in detail.

Build it without code

You could hand-write table-based HTML and inline every style — or you can design it visually and let the build be handled for you. Mirosign’s free email signature generator lets you design a signature, see it render live, and export clean, inline HTML that works across clients. No developer, no IT ticket, no per-user licence.

If you already have a signature you love, you can even import your own HTML design and manage it through Mirosign instead.

Install it in your email client

Once you’ve exported your signature HTML, installing it takes a couple of minutes. The exact steps differ per client, so follow the guide that matches yours:

• HTML signature in the new Outlook
• Gmail app on iPhone
• All installation guides → (Windows, Mac, iPhone, iPad, Android and browser-based)

Get the legal and privacy details right

If you run a UK limited company, your emails are considered business letters — which means they must legally show your registered company name, registration number, place of registration and registered office address. Many signatures quietly break this rule. We cover the exact requirements, plus disclaimers and GDPR considerations, in our upcoming legal guides.

Mirosign is also built privacy-first — no tracking pixels quietly reporting on the people you email.

Keep it consistent across your team

One person’s signature is easy. Fifty people, all slightly different, is a branding problem. Rather than emailing screenshots and hoping, a shared design keeps every team member on-brand automatically — and Mirosign does it without charging per user.

Frequently asked questions

Do I need to know HTML to create an email signature?

No. You can design one visually in Mirosign and export working HTML without writing any code.

Why does my signature look different in Outlook and Gmail?

Each client renders HTML differently and strips certain styles. Using inline styles, web-safe fonts and a simple layout — as Mirosign’s output does — keeps it consistent.

Should my logo be an attachment?

No. Attached images show as a paperclip and bloat every email. Use a hosted image instead.

Ready to build yours? Design a professional email signature free with Mirosign →