Bip39 Passphrase Though it utilizes BIP32 approach it is possible to however import BIP39 seeds into Electrum wallet. Also in addition to BIp32 There is certainly BIP44 Variation which some wallet use to the era of seeds. You should make sure to make it possible for recovery from mnemonic phrases https://fatallisto.com/story8472894/seed-phrase-examples-the-smart-trick-of-bip39-phrase-that-nobody-is-discussing