Any alien (excluding Mainland Chinese) with a valid resident certificate and ARC No. issued by the National Immigration Agency may file an individual income tax return online for the year 2020 from May 1st, 2021 to May 31st, 2021. After downloading the electronic tax-filing program at https://tax.nat.gov.tw/, taxpayers can log into the system via an Alien Citizen Digital Certificate, Registered National Health Insurance Card with password, a Financial Certification Authority (Financial CA), or by entering the ARC No. and Passport/Resident/Permit No. as specified on the ARC as of January 31st, 2021, and follow the instructions given in the program to file income tax returns online. If any document is required for filing, taxpayers shall submit it in person or send it by post before June 10th, 2021.