If a husband gives talaq, does he need 2 witnesses and would I get a divorce certificate?

There are no witnesses that are required for Atalaq. It doesn't need to be written. It can just be verbal. I always recommend, though, that in this particular situation, you have something written so that there's no dispute going forward in terms of whether it was given, whether it was not given and so on. So to be on the safe side, then it should be documented if possible. But it does not need to be documented and you do not need to have any witnesses.