You can’t delete in app if it was previously available in the store, but you can remove it from the store.
To remove your app from sale on the store
- Open the App Details page for the app, as described in Creating an iTunes Connect Record for an App.
- Click Pricing and Availability.
- Select Remove from Sale from the Availability section.
- Click Save.
The status changes to Developer Removed From Sale. Within 24 hours, your app won’t be seen on the store.