72625 posts
Hi ruchir88888, and welcome to MySwissAlps!
First of all, I would like to clarify whether you mean a ticket for the trip, or a seat reservation.
Seat reservations are not compulsory, so you would not have to show it to the conductor. Therefore, just having it on your phone would be OK.
If you bought an actual ticket online from the SBB Ticket shop, please read all the relevant information (under several different headings) at the following link, to make sure you can meet the requirements for displaying a valid ticket on your phone:
http://www.sbb.ch/en/travelca rds-and-tickets/buying-options/online/faq.htm l?WT.ac=linklistteaser-ts-faq-default
Alpenrose