Can i modify an apk file using android studio ?

Answer 1

maybe..(if its open sourced, then yes)

Answer 2

Try using application that will fetch the entire source code of the apk you are about to be modified.For eg Show Java app for Android will give you the entire source code of an Android app if it's open source .Then you can upload those files in your Android studio .Do what you want to modify in those files from Android studio itself.

Answer 3

to modify an app you have access to it's source.
and modifications are made with respect to your need.
if you want to add/remove ads or anything similar to this then you have to modify Manifest.Xml, if you want to change dependencies, modify gradle file.

Note: Modifications in An App without proper permission is an illegal act and unlawful . so please use this information as Educational purpose only.