Unverified users that have not completed KYC can still use our app, but will be restricted from some features such as depositing in fiat currency or participating in various campaigns. Generally we recommend all users to verify as soon as possible so they can enjoy all of our features and the strategic flexibility that comes along with it. 

More on our KYC process: https://www.btcc.com/en-US/support-center/detail/16402715792665