After restore my Iphone the restrictions key follow loss

My friends apple support:

restore my iphone 6 from iTunes account to rescue the off in restrictions tab in settings because loss or not remember the key for restrictions...ok?.

So, i did all procedure of back up and all right, but when go to restrictions tab on settings again the key login appear and not remember this....

please, how get it back or clean this step to have restrictions tab again in off?, how get it back this key?

Thanks.

ZIPAPPLE