1. Go to "File"

2. Then go to "Options" in the left menu bar

3. Then go to "Mail" in the left menu"

4. Then click "Stationery and Fonts"

5. Click the tab called "Email signature"

6. Click "New"

7. Type what you want your signature to be in the box below

8. Then in the drop downs in the top right for "Choose default signature" set this to the new one you have just created