To sign up for a Microsoft Azure Cognitive Services API Key for the Face API, go to https://azure.microsoft.com/en-us/services/cognitive-services/face/ and click Try Face:
Click to sign in:
Enter a name and click Create:
Open the resource:
Click Grab your keys and copy your keys for later use:
Note the endpoint for the keys. My endpoint is: https://northeurope.api.cognitive.microsoft.com/face/v1.0
You can now start building Azure Cognitive Services applications.