PvP-The Elder Scrolls Online Guide

In most MMO games PvP is just a separate part that does not affect the game itself. But in Elder Scrolls Online it is implemented into general game story as Alliance War. Three alliances are fighting between each other and you are the member of one of them. Your impact into world PvP helps your faction to win Alliance War and to control Imperial City. When your faction controls the Imperial City it is possible to challenge Molag Bal and his armies.
There are no Battlegrounds in ESO and developers are not going to add them in future. All player vs. player fights take place in Cyrodiil only. On one hand, that's not good, but on the other hand, such system allows to gather all PvP fighters in one location.

Cyrodiil
Cyrodiil is a huge province where all action of Alliance War takes place. Why Cyrodiil? Because the Ruby Throne is situated here. The faction that controls the throne rules in Tamriel.
Elder Scrolls Online does not force you to fight against others and you will not have to visit Ctrodiil in your quests. PvP is not an obligation and you can enjoy PvE content in other provinces without necessity to protect yourself. Nobody can attack you outside of Cyrodiil. There are no duels in the game and if you wish to fight against other players you will have to go to the dedicated zone.
The great thing about ESO is that Alliance War does not mean only fighting against other players. There are many familiar towns where you will be able to take different quests, there are public dungeons that you can visit, dark anchors that you can destroy, Mages Guild’s books, resources for crafting, and different places for exploration. You will meet a lot of NPCs who need your help.
Map
Long-time fans of the Elder Scrolls series should instantly recognize the map, as PvP actually takes place in Cyrodiil. The province is split up into three sections for the three different Factions.

The map is quite large as it encompasses all of Cyrodiil in one zone, unlike other parts of the Map, where provinces are split into smaller zones. Travel around the map can be sped up thanks to the Wayshrines which let you teleport to other shrines, so long as your group has control of it and it is connected to the grid properly. Of course mounts can also be used to speed up land travel across Cyrodiil.
More information is here:https://www.mmogah.com/news/title/full-guide-of-the-elder-scrolls-online-player-vs-player