Accreditation is the formal process of verifying and approving who may attend an event and in which role, such as press, speaker, exhibitor or VIP. It controls access rights and is common at congresses, trade fairs and association events.
Accreditation goes one step beyond simple registration. It checks identity and role before granting access, which matters as soon as different groups need different rights.
At congresses and trade fairs, press, speakers and exhibitors often need separate zones, badges and time slots. Accreditation makes that manageable.