Living in Zurich and we both parents are Indian nationals.
We were asked to submit
1. Both parents birth certificate
2. Marriage certificate
We are told starting late 2021/ early 2022, there is a change in law that states certificates we share are to be verified in person by Swiss authorities (or someone nominated by them). We requested more info on the law but did not succeed in getting it!
It does not matter if certificates are apostliled or not. In person verification is mandatory we are told.
Both our families back in India were visited for questionnaire + Offices that issues birth certificate were visited + Marriage certificate issual office was visited too
Right from the day we submitted our documents, it took almost 8.5 months to receive birth certificate.
After 4/5 months as I wanted some confirmation about birth for my work related stuff, authorities issued us a birth confirmation certificate and was valid for 2 months. Right from the time we asked for this, it took 2-3 weeks to receive this confirmation
You can apply for Indian passport with this confirmation and don't have to wait for birth certificate.
Once birth certificate is issued, reach out to Kreisburo and apply for a residence permit. You will be given an appointment for biometric post which your kids shiny residence card arrives in your mailbox
hope this helps!!