This letter serves as my resignation from (ใส่ชื่อบริษัท) as of (ใส่วันสุดท้ายของการทำงาน), which will be my last day. It has been a REAL pleasure working at (ใส่ชื่อบริษัท). I want to thank you for giving me great support, understanding, and encouragement during my employment here. I wish you and everyone the best of luck and much success in the future.
Sincerely,