You keep changing the user interface! So frustrating. I lost my signature in recent update. Cannot work out how to sign
I hope the below mentioned steps solved your query. Do let us know in case you have any other issue.
Adminsagrover (Admin, Adobe) commented
Can you please share detailed steps of the issue you are facing?
Additionally in order to create a new signature, please go to the Fill and Sign app and then click on Sign. You can add new Signature/Initials from the drop down.
Hope this helps !!