To accommodate App Indexing is necessary to implement a mechanism for displaying the corresponding page of the direct application called deep linking, by implementing this deep link app, SERPs in app displayed on such It is a mechanism to launch the application directly from the link to the page. There is also an App Indexing API as an accompanying function, which allows you to add more detailed data, that is, annotate the URL of the application, and Google will also use Google’s autocomplete for data via this API. Has been announced.
Google had announced that it would adopt this App Indexing as an element when determining the ranking, but
it is said that it will also incorporate the App Indexing API.
Deep link test tool (Google official)