What documents do I need to extend my tourist visa in Thailand and does my landlord need to register my residence?

To extend your tourist visa in Thailand, you will need to provide several documents: an application form (available at the Immigration Office), a passport photo, copies of your passport's ID page, visa page, admitted to stay stamp, and TM6 departure card, all signed by you. The extension fee is 1,900 THB. It is also essential to check if your landlord registered your residence with the government, as it might be required for the extension process.