What is a residency letter in Thailand and how can I obtain one?

A residency letter, also known as a Certificate of Residence, can be obtained through the Immigration Office in Bangkok, especially if you have completed a 90-day report there. Alternatively, if you haven't, you can request it from your embassy, such as the US Embassy, which provides the letter for a fee of $50 and delivers it the same day. In contrast, obtaining it from the Immigration Office in Bangkok may take up to three weeks by mail, but costs only 200 baht.