CW 90 days by mail report.
Sent current original slip, copy of documents signed (passport, house registration, departure card) and filled report form by EMS mail 2 weeks before report date
Get confirmation from EMS the envelope was delivered.
Received 90 days slip back today, which is exactly 1 month + 1 day from the report date.
I strongly recommend to send report via EMS to get tracking, signature from receiver and also keep copy of current report in case mail lost for any reason.
TLDR : Answer Summary
The post discusses the process of submitting a 90-day report by mail in Thailand using EMS service. It describes the steps taken, including sending necessary documents and receiving confirmation of delivery. The author recommends using EMS for better tracking and maintaining a copy of the report in case of any issues.