You want to Factory Reset MacBook Air/Pro or want to Restore MacBook To Factory Settings then follows the video to restore your Mac step by step.

I hope it will solve your problem and make your MacBook like before.

For More Help you can try this too: Once your files are backed up, shut down your MacBook Pro. Plug it into the AC adapter, and then boot it back up. Finally, press and hold “Command-R” (the “Command” and “R” keys at the same time) to start the restore process. Hold these keys until the Apple logo appears on the screen, and then release them.