Google says that over 500 million Android devices can access Instant Apps feature, but you need to enable it using the below Guide.
How to enable Android Instant Apps:
1. Open Settings Application on your Android Smartphone.
2. Scroll down and tap on Google.
3. Tap on Instant Apps.
4. Enable It.
That's it! You can now access the Instant Apps on your Smartphone from any URL including search, social media, messaging, and other deep links without needing to install your app first.
Right now, there are over 50 apps compatible with Instant Apps, including Jet, Onefootball, Hotpads, Citymapper, Realtor, Vimeo, dotloop, NYTimes Crosswords and many more.
How to use Android Instant Apps
1. Go to a Google search page.
2. Enter your search term, such as Jet or Vimeo.
3. Tap on the first result.
4. Enjoy the app