A "bin file" is a raw, sector-by-sector copy of that data. Specifically, it contains two key pieces of information found on the NTAG215 chip used in Amiibo:
Amiibo bin files are non-executable data—they cannot run code. However, the archives (ZIP/RAR files) you download can be rigged. A file named “complete_amiibo_collection.exe” is a virus. Stick to .bin and .zip files from trusted sources like Archive.org. download amiibo bin files
You cannot directly download and write them using an iPhone because iOS blocks low-level NFC writing. You can download them to iPhone storage for later transfer to an Android or PC, but you cannot create physical Amiibo cards with an iPhone alone. A "bin file" is a raw, sector-by-sector copy of that data