It needs to be a closing bank statement, in pdf form.
I got a certificate from companies house to show I have a legit company.
I showed a page from companies house detailing I can work remotely for my business.
Made a cover note with wet signatures from the directors.
Proof of address originating country (i showed my council tax bill)
Proof of entry point into Thailand ( I showed my flight ticket).
Photo
Copy of passport
Everything needs to be a PDF unless stated otherwise. If you can only upload one file at a time, then put everything on one PDF. For example, If you need to upload multiple documents for your business, put them all in one PDF and upload that.