Box 1: verification -
Identity verification -
Modern enterprises and apps can use the Face identification and Face verification operations to verify that a user is who they claim to be.
Box 2: similarity -
The Find Similar operation does face matching between a target face and a set of candidate faces, finding a smaller set of faces that look similar to the target face.
This is useful for doing a face search by image.
The service supports two working modes, matchPerson and matchFace. The matchPerson mode returns similar faces after filtering for the same person by using the Verify API. The matchFace mode ignores the same-person filter. It returns a list of similar candidate faces that may or may not belong to the same person.
Box 3: identification -
Face identification can address "one-to-many" matching of one face in an image to a set of faces in a secure repository. Match candidates are returned based on how closely their face data matches the query face. This scenario is used in granting building or airport access to a certain group of people or verifying the user of a device.
Reference:
https://docs.microsoft.com/en-us/azure/cognitive-services/face/overview