Open es file manager, on the left side you will see where it says "library" click it then you will see "app" click it then it will show all the applications you have installed , right click and hold on the app you want then at the bottom you will see a few options click on "back up" after it's backed up look the the left side again and click on "home"> "internal storage" > "backups " >"apps" then you will see the application you backed up, next right click and hold on the application you want, then it will show options in the bottom again, click on "copy" after that , on the left side again click " home" >"internal storage" then click on "windows" > "documents" then click "paste" at the bottom then when you go to your "document" folder on your laptop you will see the apk.