If you find that you repeatedly send the same message, you may want to create a Signature file in Outlook. You can create a signature containing any information which will remain constant, save the signature, and then use the signature to send a new message or to reply to a message. NOTE: In order to select between multiple signatures, you must create a default signature file (e.g., a business, personal or even blank).

Create a Signature File In Outlook 2010 and 2013 (Windows) 

1. Choose File | Options | Mail and then click on the Signatures button.
2. Click the New button on the Signatures and Stationery window.
3. Enter a name for your new signature (e.g., "invite") and click OK.
4. Enter any text in the Edit signature text box that will not change. You may also change the message font and style if you would like.  Note: You must set default signatures for new messages and replies/forwards
5. Click the OK button to return to the Options menu.
6. Click the OK button to close the Options menu.

Create a Signature File In Outlook 2011 (Mac) 

1. Click Outlook (on the upper left) | Preferences | Signatures
2. Click the "+" at the bottom left of the screen to add a new signature
3. The window on the right side of the screen will now be active and you can draft the signature

Create a Signature File from an Existing Message

1. Open the message and choose Select | Select All in the Editing section
2. Right click on the highlighted text and select Copy
3. Follow Steps 1-6 above.
4. In Step 4 instead of typing in the message text, right click in the Edit signature text box and choose Paste.
5. Continue with Step 5 above.

Send a Message Using a Signature File In Outlook 2010 and 2013 (Windows) 

1. Create a new message.
2. Right-click on the existing signature file in your message and select the signature you want.
3. Click the Send button.

Send a Message Using a Signature File In Outlook 2011 (Mac)

1. Create a new message. 
2. Click the Signature dropdown icon that is to the right of the picture icon on the taskbar. 
3. Choose which signature you wish to send
4. Click the Send button. 

Reply to a Message Using a Signature File In Outlook 2010 and 2013 (Windows)

1. Select the message you want to reply to and click on the Reply button
2. Right-click on the existing signature file in your message and select the signature you want.
3. Click the Send button.

Reply to a Message Using a Signature File In Outlook 2011 (Mac) 

1. Select the message you want to reply to and click on the Reply button
2. Click on the signature dropdown bar from the taskbar and select the signature you want
3. Click the Send button.

Modify a Signature File in Outlook 2010 and 2013 (Windows) 

1. Select File | Options | Mail and then click on the Signatures button.
2. Select the signature file you want to modify.
3. Make any changes in the Edit signature text box and then click the OK button.
4. Click on the OK button.

Modify a Signature File in Outlook 2011 (Mac) 

1. Click Outlook (on the upper left) | Preferences | Signatures
2. Highlight the signature you wish to modify by clicking on it
3. You can now edit the signature by typing in the window on the right side of the screen

Delete a Signature File In Outlook 2010 and 2013 (Windows) 

1. Select File | Options | Mail and then click on the Signatures button.
2. Select the signature file you want to delete, and click the Delete button.
3. When prompted 'Are you sure you want to delete the selected signature? All e-mail accounts using the signature will no longer have a signature'. click the Yes button.
4. Click the OK button.
5. Click the OK button.

Delete a Signature File In Outlook 2011 (Mac) 

1. Click Outlook (on the upper left) | Preferences | Signatures
2. Highlight the signature you wish to delete by clicking on it
3. Click the "-" at the bottom left of the screen to delete the signature