Giving permission when using command?

Hi, I would like to create a command and give a player a permmision when he writes the command.

When a player writes "/help on" or "/help off"
I want it to be permission helpchat.use when it writes /help on
And when one writes /help off it withdraws permission

I am French and I do not know if I express myself properly, thank you for your help

 

Yes it's a personal plugins, it's the base of the AdminChat plugin that I modify
I would like there to be a helper grade to answer the message
We play the command / help on and he can see and write the messages in the chat
But when he does the command / help off he is not spamer share the message of the chat

 

Hey,
guess I can code something for you,
lets private if you're interested,
- am french too ^^