Do I need to have the owner of the house I’m staying in fill out a tm30 for me as a tourist staying 60-90 days?
And if I have to, does it have to be the owner or can it be the person (my gf) renting it from the owner?
TLDR : Answer Summary
As a tourist staying in Thailand for 60-90 days, you will need the TM30 form completed by the property owner, whose name must be listed on the blue Tabian Baan (house registration book). This must be the legal owner, and if your girlfriend is renting, she cannot fill it out unless she has the owner's permission and necessary details to do it. While not all locations require a TM30 for processes like a 30-day visa extension, some places, such as Phuket, have different policies.