When we talk about deep linking for mobile app, it means creating a specific URL to open a mobile application. It separate into two formats:

1. A custom URL scheme that your app registers: scheme://videos
2. A universal link that opens your app from a registered domain: mydomain.com/videos

Deep Linking is a technique in which a given URL or resource is used to open a specific page or screen on mobile. This particular screen may reside under a series of hierarchical pages, hence the term "deep" in deep linking.
Deep linking and universal links are the gateways into your application.