1. In your Project pane, click on the little gear icon (Gears icon)

2. Uncheck the Compact Empty Middle Packages optionhttps://i.stack.imgur.com/lkezT.png
   

3. Your package directory will now be broken up into individual directories

4. Individually select each directory you want to rename, and:

• Right-click it
• Select Refactor
• Click on Rename
• In the pop-up dialog, click on Rename Package instead of Rename Directory
• Enter the new name and hit Refactor
• Click Do Refactor in the bottom
• Allow a minute to let Android Studio update all changes

Note: When renaming com in Android Studio, it might give a warning. In such case, select Rename All

5. Now open your Gradle Build File (build.gradle - Usually app or mobile). Update the applicationId in the defaultConfig to your new Package Name and Sync Gradle, if it hasn’t already been updated automatically:

You may need to change the package= attribute in your manifest.
Clean and Rebuild.

Done! Anyway, Android Studio needs to make this process a little simpler.