Use Shamir Secure Secret Sharing and BIP39 to securely distribute and reconstruct a BIP39 mnemonic phrase.
Test this utility with an unimportant seed to share and recombine parts to understand its function. (Valid test mnemonic seeds can be created at https://iancoleman.io/bip39/).
To reduce the possible risk of a malware infection capturing the inputs or outputs of this utility, it is strongly recommended that you run this tool from a secure OS, such as a live boot of tails.
Typing or storing your seed phrase in plain text on your normal desktop OS is extremely dangerous. Additionally, storing the output parts of this utility together is no safer than simply storing your seed in plain text.