Hello Rajasekhar
You can find the link here:
https://www.sbb.ch/en/tickets-offers/tickets/guests-abroad/swiss-halffare-card.html
Before you purchase the Swiss Half Fare Card, create an SBB account, which you can later use to log in to your account using the SBB Mobile App. Click here:
https://www.swisspass.ch/register/2?lang=en
When purchasing the card, choose, that you have a SwissPass account (Sign in with SwissPass), and enter the account details (e-mail address & password) you have created before, then add you and your wife as passengers and purchase the cards.
Later, download the SBB Mobile app and use the same account details to log in. The Swiss Half Fare Card for both will appear on your SBB Mobile app, as e-tickets.
Now, when you purchase tickets using the SBB Mobile app, on the screen with the ticket offers, click on the pen near the passenger details and add you and your wife there, and select for both the reduction card ‘Half Fare Card’. Then you are all set, the SBB Mobile app will now calculate the ticket costs taking half fare into account. Here is a link to see the screen images:
https://community.sbb.ch/d/26418-how-can-i-save-the-info-of-swiss-half-fare-card
On the train, show 4 QR codes: your tickets, your Swiss Half Fare Card, plus your physical passport or government ID card (physical: paper copies or images of it on smartphones are NOT accepted).
Please let us know if you need additional guidance.
Kind regards,
Roland