There are plenty of ways to monetize learning apps. More specifically, you can use the following monetization models:
Subscription. Provide educational materials on a subscription basis, charging users a fixed monthly fee for using your application.
Freemium. Offer your app for free but hide premium content and features behind a paywall.
Course fee. Receive a fee from each course sold on your platform or sell your own courses.
In-app ads. Place ads in your app and earn a commission every time a user interacts with them.
Paid installs. Make your app paid and receive money every time someone installs it.
These are the most common monetization models you can leverage after publishing your application.