How to Set Up an Email Signature

A good email signature is a compact block of plain text — your name, one line for your role or company, and one or two ways to reach you — that your provider appends automatically to every message you send. Set it up once in your email settings, keep it to about four lines, and skip embedded logos, and it will render reliably in Gmail, Outlook, Apple Mail, and every phone that opens the message. Here is exactly what to include and where each setting lives.

What to put in — and the four-line rule#

The most common mistake is length. A signature that runs longer than a short reply looks amateurish and buries the one detail people actually want. Cap it at three or four lines:

• Line 1: Full name
• Line 2: Role — Company (drop this for personal mail)
• Line 3: One phone number or one link — whichever you genuinely want used
• Line 4: Email address or website URL

Resist the urge to list a mobile, a landline, a fax, three social icons, and a mailing address. Every extra line dilutes the ones that matter. If you are a freelancer, a single portfolio URL usually beats four social links. If you work at a company, a job title plus one direct number is plenty. A useful gut check: read your signature aloud, and if it takes longer than five seconds, cut a line.

Keep the visual width tight too. Lines longer than about 60–70 characters wrap awkwardly on narrow phone screens and in reply threads, splitting your name from your title.

Set it up once so it attaches automatically#

Every major service stores your signature and appends it for you. The menus differ, so here are the exact paths.

Gmail (web)#

Click the gear icon in the top right, then See all settings, and stay on the General tab. Scroll to the Signature section, click Create new, give it a name, and type your text in the box. Below it, set Signature defaults — one dropdown for new emails and one for replies/forwards (you can choose "No signature" for replies to avoid stacking). Scroll to the very bottom and click Save Changes, which is easy to miss; nothing saves without it. Gmail allows multiple named signatures and caps each at 10,000 characters.

Outlook#

In the new Outlook and Outlook.com, open Settings (gear) > Mail > Compose and reply, and edit the signature under Email signature, then assign it to new messages and replies from the dropdowns. In classic Outlook for Windows, it is buried elsewhere: File > Options > Mail > Signatures button, where you can also assign different signatures per email account.

Apple Mail (macOS)#

Open Mail > Settings (older versions say Preferences) > the Signatures tab. Select the account in the left column, click + to add a signature, and type it in the right pane. To make it apply, pick it from the Choose Signature dropdown at the bottom. Tick "Always match my default message font" so your signature does not clash with the rest of the email.

Wherever you set it, decide deliberately whether it should appear on new messages only, or on replies too. Most people want the full version on new mail and something minimal on replies.

Images, logos, and formatting that survive the trip#

Embedded images are where signatures most often break, so treat them with caution.

When you paste a logo into Outlook, it does not travel as a live web graphic — Outlook attaches it inline as a file like image001.png, which can show a paperclip icon, get stripped by strict mail servers, or arrive as a broken box. Many clients also block external (hosted) images by default, showing "Images are not displayed" until the reader clicks to load them. That means anything critical hidden inside a graphic — a phone number, your title — can simply vanish. Rule: never put text-only-in-an-image, and always keep a plain-text fallback.

If you do include a logo, get the details right:

• Sizing for sharp screens: export the image at twice the display size, then set the displayed width to half. A logo shown at 200px wide should be a 400px file, so it stays crisp on high-DPI and Retina displays.
• Dark mode: a logo with dark text on a transparent background disappears against the dark backgrounds Gmail and Apple Mail use at night. Add internal padding on a solid chip, or use a version with enough contrast to read either way.
• Fonts: stick to web-safe families — Arial, Helvetica, Georgia, Verdana. Custom or downloaded fonts will not load on the reader's machine and silently fall back to a default, so do not rely on them.

Skip long inspirational quotes. They add weight, rarely get read, and clash with the professional tone you are aiming for. A single thin divider rule above your details is all the decoration most signatures need.

Mobile and reply versions#

Your phone needs its own, leaner signature, and it lives in a completely separate setting from your desktop one.

• iPhone / iPad: Settings app > Mail > Signature. You can set All Accounts to one shared line, or tap Per Account to give each mailbox its own. The default "Sent from my iPhone" is worth replacing with just your name and one contact detail.
• Android (Gmail app): open the app, tap the menu, Settings, choose the account, then Mobile Signature. This is plain text only — no logos, which is exactly what you want on mobile.

For replies, a full signature repeated at the bottom of a ten-message thread turns into visual noise. Set the complete block for new emails and a minimal one — often just your first name — for replies, using the reply dropdowns in Gmail and Outlook described above.

Legal disclaimers: when you actually need one#

Most personal and small-business email needs no disclaimer at all, and adding a paragraph of "this message is confidential" boilerplate to casual mail just looks corporate. But there are real requirements in some places. In the UK, the Companies Act 2006 requires a limited company to show its registered company name, registration number, place of registration, and registered office address on business email, the same way it must on letterhead. If your employer mandates specific wording, use it; otherwise, leave it off.

Common mistakes to avoid#

• Never testing it. Email yourself, then open the message on a computer and a phone. This catches broken images, wrong wrapping, and dark-mode surprises in two minutes.
• Letting it go stale. An old signature sends people to a number you no longer answer or a title you no longer hold. Update it the day your role, phone, or company changes.
• Forgetting to hit Save. In Gmail especially, the Save Changes button is far below the signature box, and closing the tab loses everything.
• Fancy characters. Decorative Unicode symbols and emoji can render as empty boxes in other clients — keep to standard punctuation.

FAQ#

Should my signature be plain text or HTML?#

Plain text is bulletproof and displays identically everywhere, so it is the safe default. Use light HTML only if you genuinely need a clickable link or a logo, keep it under about 600px wide with inline styling, and always test it in Outlook, which renders HTML most strictly.

Why do my signature images show as broken boxes for recipients?#

Usually because the image was hosted externally and the recipient's client blocks remote images by default, or because an inline-attached image got stripped by a mail server. Keep logos small, host them reliably if hosted, and never store essential information only inside an image.

Can I have different signatures for different accounts?#

Yes. Gmail, classic Outlook, and Apple Mail all let you create multiple signatures and assign one per account or pick per message. Set up each version once, and switching becomes a single dropdown choice.

How often should I update my email signature?#

Only when the facts change — a new job title, phone number, company, or website. There is no schedule to keep, but treat any of those changes as the trigger, because an inaccurate signature quietly undermines the professionalism it exists to project.