What is the TM-30 form for visa applications in Thailand?

1.) to directly answer your question, it is the TM.30 (ตม.30) that all landlords, hotels, even home owners need to file for you (or had filed) within 24 hours of any foreigner's arrival at any particular new address. Many times the foreign tenant/renter/occupant can file the TM.30 themselves (on behalf of the owner) if they have all the documents from the owner....

2.) the TM.30 can be filed online >

3.) a separate question:

Are you applying for a Non–O "Trailing Spouse" Visa or Extension and also Non–O "Trailing Child" Visa or Extension at the Hua Hin immigration office?

sometimes when asking a question, it's easier to show the original Thai language version instead of the Google Translate version....

This is for you address registration TM.30, but PIBICS is a registration to check if you’re previously blacklisted from Thailand.

TM-30