How do I use the signature on my phone?
PRO users can add WiseStamp to the iPhone and iPad in the native iOS mail app. 
See article: Add your WiseStamp signature to iPhone!
Gmail mobile app will automatically add your WiseStamp signature once you grant API permissions. You will be able to see the signature after the email has been sent.
Unfortunately other mail apps on the iPhone don't support rich HTML signatures, so WiseStamp won't be able to be added there.
Android systems also don't support HTML signatures in any of their mail apps. We're constantly having our developers look into how we can get around this - so stay tuned!