What paperwork is required for a two-month extension based on marriage in Chiang Mai with a NON-O visa?

To extend your two-month NON-O visa based on marriage in Chiang Mai, you will need to prepare several documents including: a copy of your passport and visa pages (showing admitted date), the TM6 departure card, one passport photo, a copy of your wife's ID (front and back), a copy of your wife's housebook, a copy of your marriage certificate, and the extension fee of 1,900 THB. It is also necessary for your wife to be present during the application process.