The pvp and pve servers will be completely removed so that all servers work according to the same rules of engagement for all. Now players can simply toggle pvp on/off and consequently, they can be attacked or not by other players, all on the same server.
Pvp players will be rewarded more for their courage, but at the moment we don't know how, perhaps more exp or more rewards from quests.
The toggling can be made in major cities so that you cannot change immediately when you see a player on the horizon.
Blizzard then said that this will be a return to the origins and the starting point to make the world pvp great again, so we expect more future changes.
The aim of these changes is to build a foundation upon which we can make World PvP great again.
Remember that Battle for Azeroth will be available in the next 2018.