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How to Add a Signature in Outlook 365 (Microsoft 365)

To add a signature in Outlook 365: Desktop App: File → Options → Mail → Signatures → New → Enter signature → Set defaults → OK. Web App: Settings (gear) → View all Outlook settings → Mail → Compose and reply → Create signature → Save.

Last Updated: December 2025 5 min read

Outlook 365 Desktop App

The Microsoft 365 (formerly Office 365) desktop application provides full signature customization options.

Step 1: Open Signature Settings

  1. Open Outlook
  2. Click File in the top-left corner
  3. Click Options at the bottom of the menu
  4. In the Outlook Options window, click Mail
  5. Click the Signatures... button
Quick Access: You can also access signature settings from a new email by clicking the Signature dropdown in the ribbon and selecting Signatures...

Step 2: Create New Signature

  1. In the "Signatures and Stationery" window, click New
  2. Enter a name for your signature (e.g., "Work Signature" or "External")
  3. Click OK

Step 3: Design Your Signature

Use the signature editor to create your signature:

  • Text: Type your name, title, company, and contact details
  • Formatting: Use the toolbar to change fonts, sizes, and colors
  • Images: Click the image icon to insert your photo or company logo
  • Links: Highlight text and click the hyperlink icon to add URLs

Example signature format:

John Smith
Senior Account Manager
Acme Corporation

Phone: (555) 123-4567
Email: john.smith@acme.com
Website: www.acme.com

Step 4: Set Default Signature

In the "Choose default signature" section:

  • E-mail account: Select which account this signature applies to
  • New messages: Choose your signature for new emails
  • Replies/forwards: Choose a signature (or select "none" for cleaner replies)
  1. Click OK to save your signature
  2. Click OK again to close Outlook Options

Outlook 365 Web App

Access Outlook on the web at outlook.office.com.

  1. Click the Settings gear icon in the top-right corner
  2. At the bottom of the settings panel, click View all Outlook settings
  3. Navigate to Mail → Compose and reply
  4. Scroll down to the Email signature section
  5. If you have multiple signatures, select which one to edit or click + New signature
  6. Create your signature using the rich text editor
  7. Configure auto-apply options:
    • Automatically include my signature on new messages I compose
    • Automatically include my signature on messages I forward or reply to
  8. Click Save
Note: The web app signature editor has slightly different formatting options than the desktop app. Complex HTML signatures may render differently.

Syncing Between Desktop and Web

Important: Depending on your Outlook version and your organization’s Microsoft 365 settings, signatures may not sync between the desktop app and Outlook on the web. If you don’t see the same signature everywhere, set it up in both places.

To use the same signature everywhere:

  1. Create your signature in the desktop app first
  2. Copy the formatted signature (Ctrl+A, Ctrl+C)
  3. Paste it into the web app signature editor
  4. Verify formatting looks correct
  5. Save in both locations
Tip: Use our Outlook Signature Generator to create a signature that works consistently across all Outlook versions.

Troubleshooting Outlook 365 Signatures

"Signature doesn't appear on new emails"

  • Check that you selected a default signature for "New messages"
  • Verify you're using the correct email account
  • Close and reopen Outlook

"Images are missing or broken"

  • Ensure images are embedded, not linked to local files
  • Keep image file sizes small (under 100KB)
  • Use PNG or JPG format for best compatibility

"Formatting looks different in sent emails"

  • Outlook uses Word's rendering engine, which may alter some HTML
  • Recipient's email client may also affect display
  • Stick to simple, table-based layouts for best results

"Can't find signature settings"

  • Desktop: File → Options → Mail → Signatures
  • Web: Settings → View all Outlook settings → Mail → Compose and reply
  • If using a company account, your IT department may have restricted signature changes

Best Practices for Business Signatures

Brand Consistency

  • Use your company's official colors and logo
  • Match the style guide if your organization has one
  • Coordinate with your marketing team for approved templates

Legal Compliance

  • Include required disclaimers for your industry
  • Add confidentiality notices if required by company policy
  • Ensure compliance with email marketing regulations

Professional Appearance

  • Keep it concise (4-6 lines is ideal)
  • Use a professional headshot if including a photo
  • Limit social media icons to 2-3 most relevant platforms
  • Test how it looks on mobile devices

Technical Optimization

  • Use table-based HTML for consistent rendering
  • Host images on reliable servers
  • Keep total signature size under 20KB for fast loading

Create a Professional Outlook 365 Signature in Seconds

Skip the manual setup. Our free generator creates optimized signatures with images, icons, and perfect formatting.

Create Your Outlook 365 Signature

Related Tutorials

How to Add a Signature in Outlook (All Versions) How to Add Images to Email Signatures Outlook Signature Generator