Anyone who is self-employed in Switzerland - including sex work - must register with the cantonal AHV compensation fund. Registration takes place online or at the counter, with a tax return form and, if necessary, accounting proof.
Contributions: At least CHF 514/year (as of 2025), above this in proportion to the declared profit. Optionally expandable with BU/NBU (accident) and daily sickness benefit insurance.
Without AHV registration, there is a risk of additional payments plus interest on arrears, and in old age, supplementary benefits instead of your own pension. Advice centers such as Xenia, Aspasie, Lysistrada help with the initial registration.