What Restrictions it does here is that if we enable it for certain apps, it tends to remove those apps completely from the app menu, i.e the user can’t see them at all. Here’s how:
Step 1 : From your Home Screen, navigate to Settings > General > Restrictions.
Step 2 : Tap on Enable Restrictions.
Step 3 : You will be redirected to a screen asking you to Enter a Restrictions Passcode. Feed in your desired Passcode. ( Make sure you remember the same! ) Re-enter the Passcode to confirm.
Step 4 : Once done, you will be redirected back to the Restrictions screen where you will find a number of apps listed that are allowed.
Step 5 : Slide the switch Off to remove those apps from the app menu.
In case you want to lock your Apps individually, you will have to Jailbreak your device which is not advisable unless you are absolutely desperate and have no other way. If you are ready to do that, you may download iAppLock. Its an app that locks individual apps. Rest assured, your iPhone is in safe hands. It provides features like Passcode Lock, Pattern Lock, Customize screen locks, Touch ID lock.