If you mean the AHV application form for an old age pension, I suggest you ask at your social services office, (When I lived in Ittigen, Bern, all my stuff went through Ittigen social services office) or at the AHV office near the Bundesamt West.
Rather than asking questions and risk getting answers which don't seem to be what you are looking for, I suggest you try our old friend www.ch.ch where info on practically every subject under the sun is given - by an official source, in English.
You are very wise to plan for such an event. I live in Zurich and got some help from the Rechtsauskunft, a free legal service. They spoke English, found the proper forms and printed them, and then went over the forms with me in English.
The form is called Anmeldung für eine Hinterlassenenrente .
There may be a service in your area - I got the information from my Kreisbüro.
Some of the answers you received here were a little unnerving for me, a widow. I wish people would be a bit more sensitive when replying. I wish you all the best.
I'm not sure. I actually did call them when i turned 45 and the answer was still no. I may try again, or google a bit. Jeez, there may be thousands of francs sitting somewhere just waiting for me!!!
You also have been married a certain number of years if no kids, and only women get it if no kids, men until end of year youngest turns 18, kids until they finish school, women 45+ for life (or until remarriage).
Personally I was surprised to get it, as I expected it to be based on need, but rather, it's based on the deceased average earnings when they worked, even if they hadn't worked in years.
Having looked at all the fineprint of a widow's pension there ist still one thing unanswered:
A widow who is receiving a pension and remarries, will lose her right to the pension. Unless that subsequent marriage dissolves in less than 10 years, in which case she is once gain entitled to that pension.
But what about "Partnerschaft"? Is common-law or "living together" or having the same address, etc. also the same.
I've checked with SAV/AHV on behalf of a friend but they haven't gotten back to me with an answer yet. I wonder if any of you would know?