Can I submit my 90-day report by registered mail, and when is the right time to send it?

The conversation revolves around the process of filing a 90-day report for expats in Thailand. The original poster is inquiring about the possibility of submitting this report via registered mail, referencing the requirement to do so at least 15 days before the deadline. A comment indicates that for first-time filers, the report must be submitted in person at an immigration office.