1. The 90 day report are for people who are on long-term extension of stays (generally 1 year extension of stays)
2. You can use one of the the follow three programs:
Immigration web-portal;
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Android eServices application;
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iPhone eServices application;
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I recommend using the website though.
3. You can also submit a 90 day report through the mail, OR at your local immigration office in person. IF you have not done a 90 day report prior, you must do your first one in person or via. mail.