KYC means Know Your Customer and sometimes Know Your Client. KYC or KYC check is the mandatory process of identifying and verifying the client's identity when opening an account and periodically over time. 

To meet KYC requirements, clients must provide proof of their identity and address, such as ID card verification, face verification, biometric verification, and/or document verification. Examples of KYC documents include a passport, driver's license, or utility bill.