@Léo ********
You should do it as close to your "admitted to" date as possible, because the 60 day extension of stay based on unable to travel due to COVID-19 starts on the day you apply.
Different immigration offices have different requirements, but all require the following:
1. Your passport and:
a. a copy of your data ("picture") page
b. a copy of your most recent visa (if you have one)
c. a copy of your most recent stamp
d. a copy of your departure card
2. [May not be asked at Bangkok Immigration] A TM30, filed in the immigration office.
3. The forms (each immigration office may have different forms, and want to use their special forms). For Bangkok Immigration, the forms are located in this group in the "files" section.
4. [Not asked at Bangkok Immigration] A letter from your embassy saying you can not return, OR a print out from your embassy website saying they don’t issue the letters, OR a print out of a letter from the embassy saying they don't issue those letters.
5. 2x passport pictures
6. 1,900 THB.
Different immigration offices have different policies. *SOME* may require:
- The ID card of the property owner where you are staying
- Copies of *ALL* stamped pages in your passport