Cisco Meraki Systems Manager
The key for User Identity in Meraki is umbrella_user_identity.
By default, the Type is a text field. Instead of choosing text, you can opt for the variables provided by Meraki SM. For setting up a user identity value, choose a type.
If a user identity is selected, the field looks as shown below:
Once the configuration is pushed to the device, Meraki SM replaces the variable with the corresponding value.