What is TM30, and how do I obtain it to extend my marriage visa in Thailand?

Go twice a year to her condo for the 4 or 6weeks at a time. Easiest way out is to stay at ie airport motel 1st night, then after that go straight to the condo... the system may assume you spent the whole month at the motel being the only tm30 on record!

That is your official address in Thailand.If the owner does not want to register you in the already rented condo,means that someone else is already registered in their address.

And what to do if the owner don't want.

Your going to need your TM30 form for immigration when applying for your spousal visa extension. It was required in chaingmai for me and many of my friends that live in the area. Its easy to fill out.

It's none of the things you said.

TM30 is a requirement of all property owners in Thailand to report when a foreigner stays on their property. They must report this within 24 hours of the arrival of the foreigner. Hotels, hostels, AirBNBs, private houses, everyone in Thailand is required to do this report regardless if a foreigner stays on their property.

If you are staying with your wife, then your wife, or whoever owns the home, needs to register you as staying there. This is the TM30, and you need a copy of it for most things at immigration. The easiest thing to do is for the owner to register the address for the online TM30 system, and then they can file a TM30 in about 60 seconds, and get proof of that as an exportable PDF.

The other option is for the homeowner to go to the immigration office with their blue housebook and their ID, and fill out a paper TM30 form to report the foreigner staying there.