Need to apply for a visa extension as am unable to leave and return for my 90 days. I have a letter from my embassy now, do you know what other papers I need to take with me? Are there forms I need to fill in? Thank you so much.
TLDR : Answer Summary
To apply for a visa extension in Thailand, you need a letter from your embassy, which you already have. Additionally, you may need to bring your current visa, passport, and possibly some specific forms to fill out at the immigration office. It's also recommended to inquire about opening hours of the immigration office prior to your visit.