If I apply tourist visa multi entry is it right I need to fly out every 60 days? If yes do I need to stay outside the country few days or can I take first flight back? But can stay 6 months? And I'm going to stay with my gf in her house so what about this tm30?
TLDR : Answer Summary
Yes, with a multi-entry tourist visa, you are required to leave Thailand every 60 days. You can either exit the country or apply for a 30-day extension at a local immigration office. There is no specific amount of time you must stay outside Thailand before returning, so you can take the next available flight back. Regarding TM30, your girlfriend, as the house owner, should file it for you online, which is a quick process.