1. Copy the signature you want to use to the Windows clipboard. 
2. In Outlook on the menu bar, click File / Options / Mail.
3. Click the "Signatures" button.
4. In the Signatures and Stationery window click the "New" button.
5. Type in a name for your signature and click OK.
6. Right-click inside the "Edit signature" and select Paste or Paste Options.
7. Click OK.
8. Select the desired options under "Choose default signature".