Add note for coversion

README.md

@@ -147,6 +147,8 @@ The `encode` command takes `HRP`, `data`, and type (`bech32` or `bech32m`) as ar
     $ bech32 encode genesis 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 bech32
     genesis1qyfe883hey6jrgj2xvk5g3dfmfqfzm7a4wez4pd2krf7ltsxffd6u6nrvjvv0uzda6whtuhzscj72zuj6udkmknakfn0anc07gaya2303dnngu3sxqctqvg5v7nw0fvkwqce7auqkxv3sj5j7e8d6vu4zy5qlssvffxqccxqcfgwc98zenr3qrzk5msfgkvjnj0ejpl8zunedeqhvajry08ueg99ynwgd2sdntrq22gensffcj03r3yjv4cv4j20ee8vujxve3fssj2demyvknzwe3glqt6t954vknpdvurthpc9fpex7t97nvqryeqpjrpscap6q0zvfpgv3nxzpy6wmx24k9xcu35vuatm5zvn7t084ec7tlw2gh0av9xwumwkv02hats66l5hkwd55rwkm2q8fsd4zvqwpvqqqqtdc6rp
 
+Note: `data` must be converted from 8-bit to 5-bit units.
+
 #### Decode
 
 The `decode` command takes bech32/bech32m string as arguments and outputs `HRP`, `data`, and type.
@@ -176,6 +178,8 @@ If bech32 string has NIP-19 hrp, it will also output NIP-19 entry:
       relay: wss://r.x.com
       relay: wss://djbas.sadkb.com
 
+Note: `DATA` is data without bit conversion. When used, the `DATA` must be converted from 5-bit to 8-bit and padded as necessary.
+
 ## License
 
 The gem is available as open source under the terms of the [MIT License](http://opensource.org/licenses/MIT).