To update things like your mobile number and title in your auto-generated email signature, head to the Exclaimer email management portal here: https://bionic.cat/exclaimerMS
Login with your Microsoft credentials, update any info as needed, and click "save changes" at the top. The short video below shows this process.
Note: you can also download your custom Teams backgrounds from these same URL at the top under "Download Background." You can then upload this to your Teams or other messaging platforms for a unified background.