Usage + Quota is a licensed feature for MAS - Billing Solution. Steps to enable this feature

Step 1: Copy the Application ID from Admin Portal --> Billing -->Settings --> Azure Stack Usage Collector Settings

Step 2: Goto Admin Portal --> Subscriptions

Step 3: Choose the Default Provider Subscription ( choose the desired Subscription) --> Access Control (IAM)

Step 4: Select the application matches with Application ID (refer Step 1), copy the name of the application

Step 5: Goto Tenant Portal --> Subscriptions --> Choose the appropriate Subscription --> Access Control

Step 6: Access Control (IAM) --> Click Add to add Permissions --> Choose Role as 'Contributor' --> Paste the Application name (copied from step 4) in the Select column --> Select the member --> Click Save 

Step 7: Click Save