In my case, they asked for a translation of my passport to Thai and an affidavit (also translated to Thai) saying that I am free to marry in Thailand. These 2 documents needed to be certified by the Thai ministry of foreign affairs. Just got my docs from the attorney (translator) who managed the MFA certification.
You get a 50 day on line on the the embassy website. Once in Thailand, you go to an immigration office (in any good size city) and you ask for a 30 day extension…
this is what I just got from the Thai Embassy: Financial evidence showing monthly income of no less than 65,000 THB or having the current balance of 800,000 THB, e.g. bank statements, proof of earnings
Both non-Thai national applicants must be 50 years or older.
Must meet the following financial requirements:
Have at least an 800,000 THB deposit for at least two months before the visa application.
A monthly income of at least 65,000 THB.
A combination of security deposit and annual income of a total of 800,000 THB.
Non-immigrant type “O-A” visas are required to have a health insurance policy with a minimum coverage of 100,000 USD, including treatment for COVID-19.