What documents do I need for a 1-month extension in Thailand with a visa exempt entry or tourist visa?

To extend your stay in Thailand for an additional month using a visa exempt entry or a tourist visa, you need to prepare specific documents. Generally, you will require your passport (with a minimum of 6 months validity), a completed application form (TM.7), recent passport-sized photographs, proof of onward travel (like a flight ticket), and a fee for the extension. It is advisable to check with local immigration for any additional requirements.