Hello Sitaram
Welcome to the SBB Community. A greeting is always appreciated 🙂
Your ticket is correctly named Swiss Travel Pass. Do not use the term SwissPass as this is a product for residents, and you might confuse others when using the wrong term.
Adding the Swiss Travel Pass to the app after purchase is not possible. You could only add it if it was purchased as a registered user. Is this the case, simply use the same username and password for the SBB Mobile app authentication as you have used to purchase the pass.
Kind regards,
Roland