Is it necessary to "check-in" online at immigration every 3 months with the DTV visa of 180 days? Thanks for your help.
TLDR : Answer Summary
Yes, with a DTV visa of 180 days in Thailand, you need to do a 90-day report if you remain in the country for 90 consecutive days. This involves filing a TM30 form where you reside and visiting the immigration office with your passport.
DTV VISA RESOURCES / SERVICES