How to set downloaded apps to system apps

Let's embark, shall we?

Prerequisites
1. Root
2. Root Explorer
3. Downloaded apps
4. ES File Explorer

Procedure
1. If you don't have the apk in file form, you'll need to backup the file to have a stored file in your storage.
2. Next go to Root explorer and navigate to the location of the apk file.
3. Long press on the apk file and navigate to Permissions
Here, you are going to change permissions from
                  rw-rw-r--
                            To
                  rw-r--r--
4. Next cut and copy the file from your storage to the root system of the device storage and paste it to the root/system/app
5. Next, reboot your device for changes to take place.