To unlock access to the Warfronts feature, you will need to level a character to 120 and complete a short, introductory quest line to each Warfront. You must do the quest lines with one character of each faction to unlock both Horde and Alliance Warfront access account-wide.

Each region (Europe, Americas, etc.) cycles through phases of varying length, and with different content available as the warfront zone changes control between Alliance and Horde. Progress and remaining time for each phase can be viewed at the War Tables in Boralus and Dazar'alor.

Patrol:

  • You have access to world bosses and world quests in the warfront zone, with a portal to the zone from your faction hub
  • You cannot contribute profession items, gold, and War Resources via quests in your faction hub
  • You cannot queue for the instanced warfront via the war table

Contribute:

  • You do not have access to zone specific world bosses, world quests, or a portal to the warfront zone
  • You can contribute profession items, gold, and War Resources via quests in your faction hub to help your faction build up enough strength to attack
  • You cannot queue for the instanced warfront via the war table

Siege:

  • You do not have access to zone specific world bosses, world quests, or a portal to the warfront zone
  • You cannot contribute profession items, gold, and War Resources via quests in your faction hub
  • You can queue for the instanced warfront from the war table in your faction hub

A detailed guide can be found on Wowhead.