usual form plus a covid specific form to fill out stating the reason you can't leave the country and a declaration you understand the overstay rules. In addition one passport sized photo, a copy of every page in your passport except blank pages, and proof of address.
Looking at my local immigration office yesterday, a usually deserted place in normal times was packed with hundreds of those from Cambodia and Mayanmar seeking to be officially recognised under the government's amnesty program who have crossed illegally. I am sure if you are willing meet the legal requirements they will allow.
The usual application form and covid extension form with copies of the relevant pages of passport and proof of address and passport sized photo. My local immigration charge me 100 bht for filling out the forms for me. Easy process.
