What are the requirements for picking up a parent of a Thai child visa extension after one month?

okay if you had an extension based on being the parent of a thai child and used banked money method (400K baht in a thai bank account in your name only) there is no requirement to show the bank book when you go to get the year extension inked in after the under consideration period.

In fact the extension based on raising a thai child doesn't even have proof that the 400K baht was in your account for 2 months before you apply for it (there is no seasoning requirement on that type of extensions)

Just show up with the passport and the blue/green receipt showing you paid 1900baht for the extension (if you still have it) on the date it says, you'll be fine

You had better check with your immigration office to be sure for details for each of them.

Q do you need another letter from the bank to confirm money in the account ?

-> No, you don't need bank letter.

Q Do you need to show anything letter or bank book ?

-> usually, no. But you need to check your immigration office to be sure.

Q Also when can you withdraw money under 400k ?

-> Basically, yes. You should check your immigration office to be sure when you can withdraw money.

Q Do I need to leave the country every 90 days ?

-> No. Instead you need to do 90 days report. Cehck the first due date of 90 days report when you go back to the office to get the year stamp.