-they needed the physical passport obviously to stamp it.
-visa, and entry stamp
-tm7 form (exit card you get when your arrive in Thailand)
-application form you get at the immigration office (super simple)
-proof of insurance (I still have not got a straight answer from anyone if Covid insurance is needed for the extension rather then just normal Heath insurance but in my case I just extended mine)
-hotel reservation or lease agreement for the extension period.
-booking or proof of where your currently staying
-Thai phone number
-one passport picture
They did not ask for it but I still provided proof of my ASQ completion (paid booking)
-1900 baht
-I did not need to show a return plane ticket which was nice as every time I have to make a change it costs me so I just extended it until the end of my final extension.
-lastly, I will have to go back every 90 days from the day I arrived in Thailand and fill out a TM 47 form provided at the office (also super simple)