Northern Trail Outfitters has a custom quick action on Account that creates a new Case. How should an administrator make the quick action available on the Salesforce mobile app?

Compact page layouts are used to define the fields displayed in the highlights panel on record pages and in the Salesforce mobile app, but they do not control the visibility of quick actions.

Quick actions that need to be available in the Salesforce mobile app and Lightning Experience are exposed by adding them to the "Salesforce Mobile and Lightning Experience Actions" section of the object's page layout. This section controls the actions visible in the action bar on mobile and in Lightning Experience.

The Salesforce Mobile Navigation menu controls the tabs and items visible in the app's main navigation, not the quick actions available on specific record pages.

Creating a custom Lightning App might contain the action, but it doesn't make the quick action available on the Account record within the standard mobile experience; the action needs to be added to the Account's page layout.