Foreigners can buy mask via drugstores and pharmacies which contract with the National Health Insurance(NHI) using their NHI card or use their own identification information such as passports and Alien Resident Certificates (ARC). Consumers will be limited to only buying two masks per week (7 days), and it costs NT$10. As for foreigners who come to Taiwan on a tourist visa, will not be eligible for the rationing system at NHI-contracted pharmacies, so foreigners planning to visit Taiwan prepare their own masks before they arrive. Normal people do not have respiratory symptoms and fever is not necessary to wear a mask. Please refers to Policy of Mask, Taiwan Food and Drug Administration(https://www.fda.gov.tw/tc/includes/GetFile.ashx?id=f637165067664568881)(if the links fails, please visit FDA website), or you can refers to the following links for more information about buying masks.
https://www.taiwannews.com.tw/en/news/3871191