EPP Code, is a randomly generated complex code by a domain registrar which can contain numbers, letters and special characters. Registrars are only permitted to provide the code to the registered owner of the domain as it appears on a whois query.
The code is officially called an AuthInfo Code and an Auth-Info code by ICANN and registry operators. It is alternatively called an auth code, a transfer key or a transfer code.
The code supports transferring any domain in the above top-level domains from one Registrar to another. If the code is not provided, then those domains generally cannot be transferred.