Key file is a way to store the wallet seed phrase and private key’s in an encrypted way saved by a password, it’s not the safiest way unless it’s stored in an all the time offline storage and to always remember the set password of the key file or the wallet will be lost for ever even a missing letter or number from the key file will cause the loss of the wallet, usually key files be .json or .txt or .dat files based on the platform program and the wallet in use.
Key file
