Bip39 Passphrase. The passphrase just isn't chosen in the predefined list of 2048 words – it can be any word or phrase you end up picking. Mnemonics are illustration of entropy. Starting point will involve creating a call regarding just how much entropy you think about safe for the operations. https://mnobookmarks.com/story18742278/bip39-mnemonic-https-linktr-ee-bip39-bip39-generator-an-overview