Is it possible to create a HTML signature for the Outlook for Android app? I have been trying to get the full signature that I normally use on desktop Outlook to work on my mobile phone for the Outlook for Android app. So far I have tried multiple solutions such as 
facemail however I don't really want to pay to get it working.

This website says that the Outlook for Android app does not have HTML support but I was hoping there was some way to get it working.

Another thing to note is that my business will not allow an app other than Outlook for Android so I am limited from getting other android apps which can do the job.
As of the wtiting of this answer (9 March 2019),Outlook for Android does not support HTML signature.

There is a thread on UserVoice asking for:


  Support HTML features in signature such as images and company logos as well as hyperlinks and formatting.


However,although the request has more than 7 thousand votes, it was declined by Microsoft:


  We have had to make the decision that this isn’t something that we’re going to have on mobile. We have a team spending their time on making sure our HTML rendering and message composition experiences are rich (formatting support is coming in the future). We are still taking your votes and notes into consideration and we highly appreciate them: Sometimes we have to make decisions to improve the overall experience for the widest amount of people. Thanks for your understanding and keep letting us know your thoughts.


Maybe in the future, they will revert their decision; but for now, HTML signature is not supported in Outlook for Android. You can only add a text-based, nothing fancy signature.