Hi

Hope you are doing well. While filling the online application form, you must have uploaded the your passport size photograph, signature and finger impression. When you will enter the examination hall, the server system will scan your face and finger impression to match them with the uploaded one. The main purpose of this biometric is just to verify your identity. For more details on admission process to AIIMS ,kindly visit the below mentioned page.

https://www.careers360.com/university/all-india-institute-of-medical-sciences-new-delhi/admission