API publishers will display the Run in Postman button in the API reference and the API documentation. Below is an example of the button. Check out other examples.
If the developer selects one of the first two options, either the Postman Chrome app or Postman native apps, the collection will be directly imported to their Postman app and bring the app into focus.
If the developer selects the third option, for people who do not yet have the Postman app, they will be directed to the web view to either download a file of the collection or get the Postman app. Nothing will happen if someone without the app clicks on either the Chrome app or Postman native app options.