The Quest Window or Quest Journal (Opened via Alt+U) allows the player to view all quests their character has started but not yet completed (Except for instance dungeon quests and Battlegrounds instances, which always remain once started).
To place a quest in the Inactive tab, right click once on it and the name will turn gray. It will then appear on the Inactive tab instead of Active. Right clicking the name again will bring it back to the Active tab. Moving the quest back and forth has no effect on whether you can continue it or not.
The Quest Window was redesigned after Renewal. In addition to the redesigned Quest Window, if a player kills a monster for a current quest a notification box will appear above their character’s head. If enabled the first 5 quests listed in the active tab will appear on the right side of your game window with a basic quest description.
Not every quest has a quest window component. Those quests who have quest window walkthroughs can be found in this category as well as by having their infobox in gold. Additionally, the Quest Window guides are not comprehensive, and do not specify the exact coordinates of the next NPC or location the player must visit. It is highly recommended to continue using the wiki guides along with the in-game walkthroughs.