If you have a website and an app you might want people navigating to your website on a device with the app installed to instead go straight to the app.
If that's what you want it's easy to do.
You just need to tell your app which website. It's just a little addition to the manifest:
Ignore the colored wiggly lines indicate that you need to declare the uap3 namespace alias:
Also add it to the IgnorableNamespaces list.
Then you tell the website about the app. Add a file named 'windows-app-web-link' to the root of the site that returns JSON like the following.
When the app is Activated you can detect being launched this way by checking for activation of the kind ActivationKind.Protocol and then query the Uri to get the path that would have been viewed on the website.
You'll find more on this and another example at