What proof does my friend need for immigration if he stays at my residence in Thailand?

When a foreigner stays at a residence in Thailand, the landlord or residence owner is generally required to file a TM30 form with immigration within 24 hours. However, this requirement may vary by location; in Bangkok, it is often overlooked. If your friend does not plan to visit an immigration office, it is likely that filing the TM30 form is unnecessary. Essentially, no formal proof is needed, but it is advisable for your friend to have your address written down in case immigration inquires.