As of January 22nd, for fully vaccinated persons a negative Covid test is no longer required to enter Switzerland. The validity of vaccination certificates has been reduced to 270 days, meaning that your second jab or booster jab must not be more than 270 days ago.
Only travellers by air or long distance bus need to fill out a Swiss Passenger Locator Form.
A very useful tool is the interactive official Swiss Travelcheck website which will inform you if you will be allowed to enter Switzerland and what requirements you need to fulfil, based on your individual data.
If you do not have an EU or UK vaccination certificate, which are necessary to enter restaurants etc., please see this post on Applying for a Swiss Covid Certificate.