When is my 90-day reporting due for my O-A visa, and where can I report it if I'm away from Phuket?

The user is inquiring about the 90-day reporting requirement for their O-A visa, specifically needing clarification on the due date for reporting to Phuket Immigration since they arrived in Thailand on January 21, 2019. They are uncertain about how to report if they are traveling in Thailand, particularly to Khon Kaen, around the reporting date of April 15th, and are also asking if online reporting is an option.