You need to verify your identity in order to use your Revolut account. This policy is in line with a banking regulation commonly known as 'Know Your Customer’ (KYC) and is the process of a business verifying the identity of its clients. It is simply an anti-corruption and fraud measure.
Until you have completed this step, you are not bound by Revolut’s General Terms of Service. Any card top-ups or bank transfers you send into your Revolut account before verifying your identity will be made at your own risk and are subject to applicable fees.