EPP code
An authorization code (also called auth-code or transfer code) the gaining registrar requires to pull a domain from the losing registrar. The 'password' for a domain transfer.
How transfers work
Unlock the domain at your current registrar, request the EPP code (usually emailed to the admin contact), submit it to the new registrar’s transfer form, and approve the transfer email at the gaining side.
Timeline
Most gTLD transfers complete in 5-7 days unless the losing registrar holds for the full 7-day objection window.