Bip39 Derivation Path. Theoretically, you can think out the mnemonic phrase by his own, but It's not Protected, because a human can not do an incredible work with the random era. The ultimate way to secure a single’s wallet is usually to take a mnemonic phrase generated by the program https://single-bookmark.com/story18794112/seed-phrase-generator-javascript-top-bip39-word-list-txt-secrets