You are going to go to IT Square Laksi Plaza temporary office, just next to Lak Si station of SRT Dark Red Line.
You will go here.
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They provide a queue number when you get the documents checked. You wouldn't have to stand in line for your turn.
Also, there are a waiting area with chairs.
And you can book online here, so don't have to wait too long
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Unless she has a history of staying in Thailand with Covid extension(s), BKK barely asked for TM30. But you can do her TM30 by yourself in Bangkok if your landlord doesn't do for you. Refer to this post by Tod Daniels for self-filing TM30.
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