What is the correct way to fill out the Affidavit of a Family Member Form for visa extension in Thailand?

The Affidavit of a Family Member Form is required for visa extensions involving support from a Thai child. The form needs to be filled out in three parts: the first by the family member (which can be anyone like a wife or mother-in-law), the second with your details, and the third includes signatures—one from the family member, one from the immigration officer, and a possible witness. Witness requirements may include providing a house book and ID copy. Form STM.10 must be filled out by the Thai citizen child or by the foreign parent if the child is underage, and this form is mandatory at Thai Immigration offices.