How to extract the android app from phone ?

Prerequisite: Rooted device

Using ES File Manager

1) Open ES File Manager
2) Click on the menu button of your device
3) Click on "Manager"
4) Click on "App Manager"
5) Long press on app you want to extract
6) Click on "backup"
7) Extracted .apk files will be placed on the "backups" directory of your sd card

Using ASTRO

1) Open ASTRO File Manager
2) Click on the menu button of your device
3) Click on "tools"
4) Click on "Application Manager/Backup"
5) Choose apps to backup and click on "backup" to finish
6) Extracted .apk files will be placed on the "backups" directory of your sd card