I have 8 generation iPad. Does it have face recognition

No. FaceID requires a TrueDepth camera sensor that is only found on recent iPad Pro models.

Your iPad8 has TouchID. TouchID and FaceID are not found together; it’s one or the other - not both.

No.

Sorry.

Base model iPads and the 2020 iPad Air 4 lack the necessary FaceID, TruDepth front facing camera needed for FaceID use.

Sorry.

iPads with Face ID:

iPad Pro 12.9 (4th gen)

iPad Pro 12.9 (3rd gen)

iPad Pro 11 (2nd gen)

iPad Pro 11