Is it mandatory to provide mobile number or email id for Aadhaar enrolment?

No, it is not mandatory to provide a mobile number or email id for Aadhaar enrolment of Resident Indian (email is mandatory for NRI and Resident Foreign National).
But it is always recommended to provide a mobile number and email id so that you get updates regarding your Aadhaar application status and can get a number of services based on Aadhaar through OTP-based authentication.