You might want to read about OP_RETURN and memo protocol
https://www.google.com/search?q=bitcoin+op_return
https://www.google.com/search?q=op_return+memo+protocol

memo.cash is utilizing BCH blockchain, OP_RETURN maximum size is 220 bytes
memo.sv - BSV - 65 kilobytes
(BTC won't work because it's too expensive)