How to unpublish/delete Android and iOS app ?

Here are the steps to unpublish the Android app: 

1. Login to Google developer console. (https://play.google.com/apps/publish)
2. Select the app.
3. Go to store presence on the Left panel.
4. Select Pricing & Distribution.  

    5. Click on the Unpublish button in App Availability section.  

    6. Submit the update. 

Here are the steps to unpublish iOS app : 

1. Login to iTunes Connect. (http://itunesconnect.apple.com)
2. Select My Apps ans select your app.
3. Go to Pricing & Availability on left panel.

    4. Select "Remove from sale" option from Availability section.

    5. Save. 

Note : Google and Apple developer platforms doesn't allow to delete the app, we can only unpublish them and make unavailable for download. 

Thanks :)