If you are staying at a private house, you need to provide an invitation letter from the owner.
For requirements, please check the website of the Thai embassy/consulate where you are applying first. Your question is being answered there.
***************************************************************************************************************************************
*****
-non-immigrant-visas?page=5d6636cd15e39c3bd
*****
dd&menu=5f4b6eb3f6ae4b
*****
2c562#6