Bip39 Passphrase Generator. At first you should keep it Independently out of your seed. Possessing your seed along with your passphrase in the exact same locale defeats the purpose of using a passphrase to start with. BIP39 specifies a list of 2048 words from which the mnemonic phrase is preferred. https://social4geek.com/story4335037/bip-39-https-linktr-ee-bip39-helping-the-others-realize-the-advantages-of-bip39