How Is a Private Key Typically Represented (E.g. Format)?

A private key is fundamentally a large, random integer. It is commonly represented in several formats for user convenience and compatibility.

The most raw form is a 256-bit binary number. It is often encoded into hexadecimal format (64 characters), or more commonly, into Wallet Import Format (WIF) which includes a version byte and checksum for error checking.

The seed phrase is a human-readable representation for backup.