Is it possible to obtain ITN number in Thailand without having a working visa?

I have retirement visa ..

 

Thanks for your help ..

if you mean taxpayer ID Number....yes.  Revenue Office will give you one and file a return for you.  First thing is to go to your bank and get a statement of withholding s.  It's free and easy.  You will likely need to go to your home branch, where you opened the account.  I am getting 3500 back from interest withholdings.