Bip39 Online. The passphrase is just not chosen with the predefined list of 2048 words – it could be any word or phrase you select. BIP39 is a design implementation that lays out how copyright wallets produce the list of words (or "mnemonic codes") that make up a mnemonic sentence, https://sociallytraffic.com/story3528399/bip39-mnemonic-https-linktr-ee-bip39-bip39-wallet-can-be-fun-for-anyone