Coming from Canada, I normally purchase a Swiss Rail Card, which for around 400 CHF gives me 7 days of unlimited travel on most of the Swiss rail network as well as on most public transit and Postbusses.

I don't know what options are available to residents of other European countries, but you can check MySwitzerland.com for information about your country or
https://www.sbb.ch/de/freizeit-ferien/inspiration/internationale-gaeste/swiss-travel-pass.html

Regards

Mike C