If you are using Xcode 9 or later, you must use your asset catalog (see image below) to provide the App Store icon for your application, as shown below, and there is no other way . Thus, it would be easy to prepare. for the release of the App Store. Basically, you can use Xcode for customization, instead of going to iTunes / App Store Connect.
If you are using Xcode 8.3.3 or earlier, you must use iTunes Connect to download the App Store icon.
At this time (September 2017), you cannot run applications created using Xcode 9 because it is still in beta. If you want, you can wait one or two more days until the Xcode 9 GM build comes out. Your build will fail during the boot process if you use Xcode 9 without adding an App Store icon resource.
For more information read this.

Badhan ganesh
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