Here’s a quick guide on how to change - translate app’s name according to devices’s language using APK Studio Editor
- Decompile the APK
- Go to Resources - > values → strings
- Find the language you want for example Greek, right click and choose edit resource
- Add
<string name="app_name">translated app’s name</string>and save changes
- Do the same for all languages that you need . Do not forget to add also to the default string otherwise it won’t work
- Then open the Manifest: AndroidManifest.xml
- Edit the Manifest
- Change app tag to android:label="@string/app_name
- Recompile the APK and you are ready !
Hope you like it 
