Hello arlynbuond22
After creating an account, it is not possible to add tickets that have been purchased before the account creation. Only tickets which you buy now will appear on your account and in the SBB Mobile app.
You are welcome to show your passes as PDF documents. In the SBB purchase confirmation e-mail, there should be the link to add it to your wallet. However, from a ticket inspector perspective the scanning of your Swiss Travel Pass is easier when you show it from a PDF or if you take a screenshot of the QR code and show it from your image gallery.
Please bear in mind, e-tickets require the physical passport or ID (no copies, no photos).
Kind regards,
Roland