I did my 90-day report on the due-date yesterday using the Web application in Google Chrome on macOS (Catalina). A couple caveats. The first time I submitted the application I got the notice that I should go visit the immigration office. Instead, I clicked the "back" button and examined the data I'd entered. I noticed that I had incorrectly used the due date for the 90-day report as the "Permitted-to-stay" date. Oops. After I entered the correct permitted-to-stay date from the Extension-of-Stay stamp in my passport and then clicked on "Submit", the application was accepted and approved instantly. I only had to go back to the start page and select the "Check Status" option to download the receipt to print and put in my passport.
Other comments for others who attempt to do it in the online web page. If you have previously used the online web page to do the report, the web page will display a drop-down showing the value you entered the last time you did it. Just clicking on that drop-down value makes filling out the forms easy (assuming the data hasn't changed since the last time you filed online). Also, if any input field has a small icon at the right-end of the field, click on it to get a list of items to choose from. Don't try typing, for example, your district, sub-district, or province name. Use the drop-down list instead.
