Access the CAS web management console.
Navigate to System > Licensing - Not showing
All CAS-MA licenses CAS appliances do not have the license tab, under "System", in the GUI.
ISG CAS-MA
This is by design.
This is specifically for the Content Analysis appliance that is a CAS-MA, and with the ISG-MA-SUB SKU. See the snippet below
Note: For an MA license, this is expected. The only tab under "System" should be "Identification". See the snippet below, for what's expected. So, all's OK.
To install/update license on CAS, please utilize the CLI for the same. See the snippet below, for requisite guidance.