Example using the [RickRoll.nfc](https://github.com/UberGuidoZ/Flipper/blob/main/NFC/Fun_Files/RickRoll.nfc) file. Leave the data in pages 1 through 6 alone (though not always true, but it is for YouTube links.)
This is simply the YouTube "[share](https://support.google.com/youtube/answer/57741)" link encoded into HEX and split into 4 byte chunks. See for yourself...
The last byte in page 6 (0x04) defines what type of encoding ([data sheet](https://www.nxp.com/docs/en/data-sheet/NTAG213_215_216.pdf) and [URI identifier codes](https://learn.adafruit.com/adafruit-pn532-rfid-nfc/ndef)). To convert your link to HEX, use anything such as an [online tool](https://onlinehextools.com/convert-ascii-to-hex).
One limitation is the URL will be truncated if it goes beyond page 11! If your URL is less than exact, pad it with 00, making sure page 12 stays as "FE 00 00 00". Note that [TinyURL](https://tinyurl.com/app) links appear to fit well and conversion/use is free. If your link doesn't launch automatically when scanned, try using a different URI identifier.