O Visa. Come on tourist visa then go to immigration office in your Provence. It’s mountains of paperwork but you can do yourself. You need 800,000 bhat in your account, letter from the bank signed that day by the bank manager, copy of your bank book with a transaction dated the same day you go to immigration, a bank statement printed that day, your TM 30 ( proof of residence/permanent Thai address ), your Passport and $. They will also have you hand draw a map of your neighborhood in front of them. Google can help with all the requirements. Then, every 90 days you must report to immigration. Best of luck.