How to Create an Email Signature in Outlook 365 — Step-by-Step Guide (2026)

Learn how to create, edit, and add an email signature in Outlook 365, Outlook desktop, and Outlook web. Step-by-step guide with screenshots for Windows, Mac, and browser.

Published April 6, 2026 · 8 min read

Open the Email Signature Generator →

Create a Signature in Outlook 365 (Web)

Step 1: Open Settings

  1. Sign in to Outlook.com or your Microsoft 365 account
  2. Click the gear icon (⚙️) in the top-right corner
  3. Click "View all Outlook settings" at the bottom

Step 2: Navigate to Signatures

  1. Select Mail in the left sidebar
  2. Click Compose and reply
  3. Scroll to "Email signature"

Step 3: Create Your Signature

  1. Click "+ New signature"
  2. Name your signature (e.g., "Work" or "Formal")
  3. Type or paste your signature in the editor
  4. Format with bold, italic, colors, and links
  5. Click Save

Step 4: Set as Default

  1. Under "Select default signatures":
  • For new messages: Choose your signature
  • For replies/forwards: Choose the same or a different signature
  1. Click Save

Create a Signature in Outlook Desktop (Windows)

Step 1: Open Signature Settings

  1. Open Outlook desktop application
  2. Go to File → Options → Mail
  3. Click "Signatures..."

Step 2: Create New Signature

  1. Click "New"
  2. Name your signature
  3. Use the editor to type and format your signature
  4. To add an image: click the image icon and browse to your file

Step 3: Assign to Accounts

  1. Select your email account from the dropdown
  2. Set as default for new messages and/or replies/forwards
  3. Click OK

Create a Signature in Outlook for Mac

  1. Open Outlook → Preferences (⌘ + ,)
  2. Click Signatures
  3. Click the "+" button to add a new signature
  4. Type or paste your signature
  5. Close the window — it saves automatically
  6. In a new email, click Signature in the toolbar to select it

Add an HTML Signature (Professional Design)

The built-in Outlook editor is limited. For professional signatures with logos, social icons, and clean formatting:

  1. Design your signature using TooStamply Email Signature Generator
  2. Copy the HTML signature with one click
  3. Paste into Outlook:
  • Web: Paste directly into the signature editor
  • Desktop (Windows): Paste into the signature editor — HTML is preserved
  • Mac: Compose a new email, paste the signature, select all (⌘+A), then copy and paste into Signature preferences

Why Use an HTML Signature Generator?

  • Consistent formatting across all email clients
  • Clickable social media icons and links
  • Professional logo placement with proper sizing
  • Mobile-responsive design
  • One-click copy — no coding required

Edit an Existing Signature in Outlook 365

Web:

Settings → Mail → Compose and reply → Click the signature name → Edit → Save

Desktop (Windows):

File → Options → Mail → Signatures → Select signature → Edit → OK

Mac:

Preferences → Signatures → Select signature → Edit in the text area

Common Outlook Signature Issues

Signature not showing on replies

Make sure your signature is set as default for both "New messages" AND "Replies/forwards" in the signature settings.

Images not displaying

  • Use images hosted online (URL) rather than embedded files
  • Keep image width under 600px
  • Use PNG or JPG format (avoid BMP or TIFF)

Formatting looks broken

  • Avoid using complex CSS — stick to inline styles
  • Use table-based layouts (TooStamply does this automatically)
  • Test by sending to yourself on Gmail and a phone

Signature too large

  • Keep the total signature height under 150px
  • Compress images before inserting
  • Use 3–4 lines of text maximum

Related Guides

Create your professional email signature →

Frequently Asked Questions

How do I create an email signature in Outlook 365?

In Outlook 365 (web): Click the gear icon → View all Outlook settings → Mail → Compose and reply → Create your signature under "Email signature". In the desktop app: File → Options → Mail → Signatures.

How do I add my signature automatically to every email in Outlook?

When creating your signature, set it as the default for "New messages" and "Replies/forwards" in the signature settings. This ensures it is automatically added to every email you send.

Can I have multiple signatures in Outlook?

Yes. Outlook allows you to create multiple signatures and switch between them. Create separate signatures for formal, informal, internal, and external communications.

How do I add an image or logo to my Outlook signature?

In the signature editor, click the image icon to insert a picture. For best results, use a pre-designed HTML signature from TooStamply — it handles image sizing, formatting, and compatibility automatically.

Why does my Outlook signature look different when received?

Email clients render HTML differently. Signatures with complex CSS may break in some clients. Use table-based HTML layouts (like TooStamply generates) for maximum compatibility across Outlook, Gmail, and Apple Mail.

Open the Email Signature Generator →