could you explain what is and what world you do it with and where and can you use pess?

You'll need to use pure essence, because regular essence can't be used to create laws.

 

 

 

Law running involves making trips to the law altar with un-noted pure essence (27 of them) and swapping it there with a law crafter who will give you 27 law runes and 27 noted pure essence. You then run the noted essence back to the bank and convert it to un-noted essence and repeat the trip. Basically you make 27 laws per trip, and all it costs you is time, while the crafter gets fast XP without having to do all the running.

 

 

 

World 66 is the place to go, if you start at the Draynor bank you should see a steady stream of people heading out to the Port Sarim docks and boarding the boat to Entrana. Once you get to Entrana, keep following the line of people up to the law altar, where you should be able to spot the crafters, they tend to wear Zamorak Robes and law tiaras.