How to implement long touch(click) with on receive hit box?

By long touch do you mean on touch devices or a computer click?

I want to implement that on mobile.By touching the hitbox and holding for a while ,then something happens.How to achieve that?Thanks!

You can then use a timer. When the hitbox is touched / hit start the timer. When Touch Input has been released stop the timer and get the time. Depending on how long you want the user to press it you can use that time for a long touch.

Thanks!I will try that!