There are many signing protocol's offered by different companies. Even with Adobe Sign there are different experiences possible: You can be using a browser (different browsers are possible) , you can be using an Adobe Fill & Sign App, and Adobe Sign app, the list unfortunately goes on. I screen shot and more information about the software you are using might help. Unfortunately, I don't use Andriod products frequently, so I might be of limited help. When I see my students trying to sign a document they are usually offered the ability to type and the ability to sign with their finger or other pointing device. I recommend switching to a written signature then switching back to a typed signature, and touching above the line you what to type your name to see if a keyboard will magically appear.
Sorry I cannot be of more help.
Mike
... View more