Not every Android user is willing to sacrifice their warranty by rooting their device. Unfortunately, in order to do jobs like app backup you would normally need root access so that you can create a backup of your app and restore it with an application like Titanium Backup for example which saves both your app and all it's data.
Fortunately for non-root users, there is a way. You will not be able to save the app's data though, but only the APK file. There are numerous apps in the Play Store that can do such job, one of them is called "File Expert" and that is what we will be using in this guide as an example.
So first of all let's begin by downloading the app from the Play Store. Once you download the app, start it up. You may skip through the features list and offers and you should then see the following options:
As you see in the marking above, you need to head into Apps. Once you are there, you should see a complete list of your installed applications:
Now if you head into the folder, you should see APK files of your backed up apps: