Hello Jishnu
Same as when you book a flight ticket:
In case you do not have a first name, please write your title (MR/MS) instead.
In case you do not have a surname, please enter your name in place of your surname. Then, write your title (MR/MS) in place of the first name.
If you are non-binary, you can also enter your name twice, once in each field. This is also accepted.
In any case, your date of birth has to be correct, this to cleary identify you among other family members.
Keep in mind that you are going to purchase the Swiss Travel Pass.
Kind regards,
Roland