How to Add an Email Signature in Outlook (Desktop, Web & Mobile)

Outlook comes in four flavors: Classic desktop, New Outlook, Outlook on the web, and mobile. Each one handles signatures differently. This guide covers all of them so you can set up your professional signature regardless of which version you use.

Classic Outlook (Desktop App for Windows)

This is the version most corporate users run. Open Outlook, then go to File > Options > Mail > Signatures. Click New, give your signature a name like "Work", and use the built-in editor to type your details.

The built-in editor is limited. You get basic formatting but no real layout control. For a properly designed signature, build it in an external tool first. Here is where the paste trick matters:

Ctrl+Shift+V pastes without formatting. Use this to strip out unwanted styles from a Word document or website copy.
Ctrl+V pastes with formatting. Use this when pasting an HTML signature from a builder tool like EmailSign.

Under "Choose default signature," assign your signature to new messages and replies/forwards separately. Many professionals use a full signature for new emails and a shorter version for replies.

New Outlook (Windows & Mac)

Microsoft is gradually rolling out New Outlook. The signature settings live in a different spot: click the gear icon in the top right, then go to Mail > Compose and reply. Scroll to the Email signature section.

Click New signature. The editor here is slightly better than Classic Outlook but still basic. You can insert images directly, which is an improvement. For HTML signatures, paste your pre-built design into the editor using Ctrl+V (Cmd+V on Mac).

One quirk: New Outlook sometimes strips background colors from pasted HTML. If your signature uses colored background sections, test after pasting and adjust if needed.

Outlook on the Web (outlook.com / Office 365)

Log in to outlook.com or your Office 365 portal. Click the gear icon, then View all Outlook settings > Mail > Compose and reply. The signature editor here is the most capable of all Outlook versions.

You can paste rich HTML directly. The web editor preserves tables, colors, and images well. Set your defaults for new messages and replies at the bottom of the section, then hit Save.

Tip: if you manage signatures for a team through Microsoft 365 admin, you can set organization-wide signatures using transport rules. But these are plain-text only and limited in design. For branded, trackable signatures, a dedicated tool works better.

Outlook Mobile (iOS & Android)

Open the Outlook app, tap your profile icon, then go to Settings > Signature. The mobile signature editor is text-only. You cannot paste HTML or add images here.

This is the biggest limitation of Outlook mobile. Your beautiful desktop signature gets replaced by plain text on mobile. Most professionals set a simple text signature for mobile: name, title, phone number. It is not ideal, but it is better than nothing.

If you need a consistent HTML signature across all devices, consider a signature management tool that injects the signature server-side before the email is sent.

Image Handling in Outlook

Outlook is notorious for blocking images by default. Recipients often see a placeholder until they click "Download pictures." To minimize this problem:

Host images on HTTPS URLs (not HTTP). Outlook trusts HTTPS sources more.
Keep images small. Files under 50KB load faster when unblocked.
Always set alt text on images. When images are blocked, the alt text appears instead.
Avoid relying on images for critical information. Your name, phone, and email should always be in text, not embedded in an image.

Common Outlook Signature Issues

If your signature looks different from what you designed, check these common causes:

Font changes on reply: Outlook applies its own default font to replies and forwards. Your signature font may not match the rest of the email. Set the compose font in Outlook's settings to match your signature.
Extra line breaks: Classic Outlook adds spacing above the signature. Remove the blank lines in the editor and save again.
Signature not appearing on replies: Check that the reply/forward default is set to your signature, not "None."

For more troubleshooting tips, see our signature troubleshooting guide.

Skip the Setup Hassle

Setting up signatures across four versions of Outlook is tedious. EmailSign lets you design your signature once and install it in any email client with a single copy-paste. It also works with Gmail and Apple Mail if you use multiple clients.