First of all if you don't know about Rooting just google that. Because rooting process void your warranty.
1. Install TWRP recovery in your mobile.
For install TWRP click on me.
2. Boot your mobile into recovery mode.
3. Just install the following Zip file .
4.After installed this zip just Reboot your device. It will take two or three minutes to boot up. Dont panic. It will take more than tow minutes again go to recovery wipe the data and cache.
5. Now you go to see the Home menu the super user app will installed.
6. If you want to verify your mobile Rooted or not by the use of Root checker app in play store.
For Unroot your Samsung J7
1. Open Super User app in your rooted mobile
2. Go to Setting
3. Click Full un root option. reboot your phone your mobille will be unrooted.





