Google Play has a feature to publish multiple apk with the same package name and different device configuration. For multiple apk's each apk has different version code and signed with the same certificate.

This feature is useful while your application is not reachable to all desired devices.

Most of the devices are covered in single apk with a different type of resources for different resolutions, different layout for different screen sizes etc. Multiple apk is useful when in some cases single apk is not supported all devices configuration or apk size exceeds 100Mb size because of resources or other technical challenges which prevent single apk to support multiple devices.

 Multiple APKs are useful in cases of :-
 

• Use different OpenGL texture compression formats.
• Use different screen sizes for each apk.
• Use different resolution for each apk.
• Build apks for different platform versions.
• Build APKs for different CPU architecture like ARM, x86, and MIPS.

For uploading Multiple APks make sure you know about rules of publishing multiple apks. Here is developer's link:- https://developer.android.com/google/play/publishing/multiple-apks.html#Rules

Tips:- For Multiple apk you can make a library for the large common code.

Happy coding !!