Upvote:3
You are definitely NOT required to book an appointment, it is only suggested. Source:
Scheduling an appointment for Biometric Enrolment is optional β walk-in clients are always welcome to submit their biometrics without a prior appointment. Note however that a planned visit with a preferred time slot via an appointment at the Visa Application Centre guarantees prompt service, thus eliminating longer waiting time resulting in inconvenience. You can schedule an appointment at the nearest Visa Application Centre, either through the VAC website or by calling the call center at +2348150199900.