I am currently living in Taiwan and I have been freelancing, too, for a while, here. I have stumbled upon a job offer which necessitates me to fill in TIN number (稅務識別碼) which I wasn’t really familiar with. I tried to do my own research a bit and thus far, what I think is the most reliable information is written in Mandarin here (https://www.mof.gov.tw/singlehtml/384fb3077bb349ea973e7fc6f13b6974?cntId=dot81803). I can decently comprehend Mandarin text but as my Mandarin isn’t perfect, I was still unsure what the text says. To my understanding, foreign individual’s TIN number is determined by their birth date followed by the two first letters of their first name, which is to say, ABDUL’s TIN number, who is born in DD-MM-YYYY, is YYYYMMDDAB. Can somebody help me verify my understanding? All answers are appreciated.
It’s your ARC number.
The second point of that document says that if you have a 統一證號, it’s your TIN. An ARC number is a form of 統一證號.
Further down, there’s also a note that anyone without a 統一證號 can apply to the NIA for one. See eg this recent thread for information on that.