Hello Rajasekhar
The Swiss Half Fare Card is valid exactly 30 consecutive days. At purchase you can define its start date yet which can’t be changed after purchase. So it should have the first day of validity set for the arrival day here in Switzerland.
Yes, you can purchase multiple Swiss Half Fare Cards with one account, simply make sure you are entering the correct name and date of birth of the passenger, and this for each card you are going to purchase.
When you plan to use the SBB Mobile app, you can add co-passengers on tab Profile. Tick the ½ checkbox to let the app know that the person has got the (Swiss) Half Fare Card.
Please let us know if we can be of any further help.
Kind regards,
Roland