Outlook Will Not Allow Me to Add a Signature

Every time I go to add a signature in my Outlook account it will not allow me to add my signature to any email account or messages. I have googled the problem and all of the suggestions I found there have not worked. I tried going to Settings, Apps, Apps & Features, Deleting Windows Desktop. However, that app or feature does not exist on my laptop. The only ones that come up are: 

1. Microsoft Office 2003 Primary Interop Assemblies

2. Microsoft Office 2007 Primary Interop Assemblies

3. Microsoft Office 365 - en-us

4. Microsoft Office 365 - es-es

5. Microsoft Office 365 - fr-fr

The next suggestion was to open a run window, search for the following key:

0006F03A-0000-0000-C000-000000000046 

and delete any keys that come up until the search comes up empty.

I have done both of these suggestions and outlook still will not allow me to add a signature. I am really hoping someone can help me troubleshoot this. Thank you!