Hello, I need to do an emergency visa run from Vietnam and was considering Thailand. I read there's a 30 days visa on arrival for French.

Do I need to fill any form or application before arriving?

Also i don't know how long i will have to stay exactly (7 to 15 days) is it mandatory to have a flight ticket to go out before the 30 days?

Do I need to show my vaccinations or to show a recent covid test?

Thank you very much for your help