1. Application to the civil registry office at your place of residence. You apply to the civil registry office at the place of residence of one of the two people. The office will tell you which documents you need for your situation. Those not living in Switzerland go via the Swiss representation abroad or directly to the office that will perform the ceremony.
2. Personal declaration. Both of you appear in person and confirm that the requirements are met: both at least 18 years old and capable of judgement, not closely related, no existing marriage or registered partnership. At this appointment, you also clarify the question of surnames.
3. Completion and appointment. If everything is in order, the office informs you of the positive outcome. From that point, the three-month period begins. The previously customary ten-day waiting period no longer exists since 2020.
4. The ceremony. It is public, usually lasts around 20 minutes, and takes place in the presence of two adult witnesses capable of judgement. You bring the witnesses yourselves, with a passport or identity card.
With foreign documents, step 1 takes considerably longer, because the office must examine them and sometimes have them verified via the Swiss representation. It is worth making initial contact with the office months before your desired date.