What are the steps and requirements for extending a NON-O visa for the spouse of a Thai national in Bangkok?

𝟭. 𝗪𝗲 𝗹𝗶𝘃𝗲 𝗶𝗻 𝗕𝗮𝗻𝗴𝗸𝗼𝗸, 𝗦𝗵𝗼𝘂𝗹𝗱 𝘄𝗲 𝗴𝗼 𝘁𝗼 𝗖𝗵𝗮𝗲𝗻𝗴 𝗪𝗵𝗮𝘁𝘁𝗮𝗻𝗮 𝗴𝗼𝘃𝗲𝗿𝗺𝗲𝗻𝘁 𝗯𝘂𝗶𝗹𝗱𝗶𝗻𝗴 𝗼𝗿 𝗜𝗧 𝗟𝗮𝘀𝗸𝗶 𝗳𝗼𝗿 𝘁𝗵𝗶𝘀 𝗲𝘅𝘁𝗲𝗻𝘀𝗶𝗼𝗻

You go to the main immigration office at the government complex (Building B) on Chaengwattana Road

𝟮. 𝗧𝗵𝗲 𝗧𝗠-𝟯𝟬 𝘄𝗮𝘀 𝗳𝗶𝗹𝗲𝗱 𝗯𝗲𝗳𝗼𝗿𝗲 𝘁𝗵𝗲 𝘃𝗶𝘀𝗮 𝘀𝘁𝗮𝗺𝗽 𝘄𝗮𝘀 𝗶𝘀𝘀𝘂𝗲𝗱, 𝘄𝗲 𝗱𝗶𝗱𝗻'𝘁 𝗺𝗼𝘃𝗲 𝗯𝘂𝘁 𝗱𝗼 𝘄𝗲 𝗻𝗲𝗲𝗱 𝘁𝗼 𝗳𝗶𝗹𝗲 𝗮𝗴𝗮𝗶𝗻?

Shouldn't need to file it again, but take a copy of that TM30

𝟯. 𝗗𝗼 𝗜 (𝘁𝗵𝗮𝗶 𝗵𝘂𝘀𝗯𝗮𝗻𝗱) 𝗻𝗲𝗲𝗱 𝘁𝗼 𝗽𝗿𝗼𝘃𝗶𝗱𝗲 𝗽𝗿𝗼𝗼𝗳 𝗼𝗳 𝗶𝗻𝗰𝗼𝗺𝗲?

You might need to show you're working, BUT on this one I don't know and you should go out to Chaengwattana and ask them before you actually go apply so you can get the documents you need

𝟰. 𝗔𝗻𝘆 𝗰𝘂𝗿𝗿𝗲𝗻𝘁 𝗱𝗼𝗰𝘂𝗺𝗲𝗻𝘁 𝗹𝗶𝘀𝘁 𝗮𝘃𝗮𝗶𝗹𝗮𝗯𝗹𝗲?

This is a general list of what can be asked for for marriage to a thai extensions (just ignore the 400K baht financial requirements as it's not applicable for foreign females married to thai males)

𝟱. 𝗩𝗶𝘀𝗮 𝗲𝘅𝗽𝗶𝗿𝗲𝘀 𝗦𝗲𝗽𝘁 𝟮𝟲, 𝗶𝘀 𝘁𝗵𝗲𝗿𝗲 𝗮 𝗰𝘂𝘁𝗼𝗳𝗳 𝗱𝗮𝘁𝗲 𝗳𝗼𝗿 𝗲𝘅𝘁𝗲𝗻𝗱𝗶𝗻𝗴 𝘃𝗶𝘀𝗮?

You can apply for a new extension in Bangkok when you have 45 days or less left on the current stamp. SO if the extension expires Sept 26th you could have applied any time after Aug 12th

There is no reason to wait until this stamp runs out as the new year extension will be added to the current expiration date.

You apply in Section L1, pay the 1900baht, get a 21 day under consideration stamp, then go back to C/W this time Section L2 on that date and get the year extension inked in