Will Face ID work on my 6th Generation iPad (Model MR7F2LL/A)?

No.

FaceID is a feature of iPad Pro models - as these have the FaceID Camera array.

No, Face ID won’t work on that particular model. Your iPad 6th gen lacks the hardware necessary for Face ID to work (cameras/LiDAR/etc.). Your iPad uses Touch ID for biometric security.

Here is a list of devices that support Face ID. >> https://support.apple.com/en-us/HT209183

It does not seem your Device is listed.

Hope this helps ;)