What documents are required for a visa extension in Thailand?

When applying for a visa extension in Thailand, specifically for a tourist exempt visa, you will generally need the following documents: a copy of your passport data page, your current visa, entry stamp, a recent photograph, the TM30 form, and 1,900 baht in cash. While some immigration offices may require additional documents like bank statements, it usually isn't necessary to show flight details or a rental contract unless the TM30 isn't filed.