I did my first 90 Day Report online at Samut Prakarn. I say online, but it was pending for two days, so I assumed it would not happen. I prepared papers and went to the office. At the office I was told that I could report but my wife and kids all had to come in person! I said that is ridiculous because normally it can be done online, to which she said, well why don't you do it online? I said I did but as it is first time, it stuck pending, Showed her on my phone, she took phone, went to a computer and said "All done!". Sure enough, when she passed my phone back the 90 Day confirmation came in by email. Sat and waited for other 3 to come through and departed. She still took all my paperwork though!
According to SP immigration ALL 90 Day reports can be done online. If you need help she gave me a Line address: @spk.90day
All I know is what happened to me. FYI