Xiaomi Mi A1 comes with a Fingerprint Scanner on the Rear. To Setup Fingerprint Scanner go to setting- Security- Enable pattern, PIN or password, Place Fingerprint on Scanner till it gets added. can add up to 5 fingerprints. Swipe Down on Fingerprint Scanner to get Notification Panel
The Fingerprint Scanner works fast and responsive is fast and responsive there was no issue, Check out below video
Mi A1 runs on Stock Android and does not come with App lock feature which is available in MIUI 9. You can use App lock from Google Play store to lock or unlock Apps. Here’s How to lock Apps in Mi A1 or How to Set up lock App in Mi A1
Xiaomi Mi A1 is powered by 3080mAh Battery with an output of 5V 2A it does not support fast charging. Charges 30min in 30%, 60% in 60min
Xiaomi Mi A1 comes in Black, Gold and Rose Gold colors is priced at Rs. 14,999 and will be available on  Flipkart and Mi.com ,Mi Home stores and other offline retail stores