Bip39 Checksum. First of all you ought to store it Individually from the seed. Owning your seed along with your passphrase in a similar place defeats the objective of using a passphrase in the first place. BIP44 defines a selected key derivation route framework that allows for handling multiple accounts https://techonpage.com/story4205794/bip39-mnemonic-https-linktr-ee-bip39-the-2-minute-rule-for-bip39-word-list