FFXIV: ARR features a robust questing system
which includes simple fetch quests, Grand Company quests, class quests, job quests and main scenario quests. All of which serve a different purpose. They do all have one thing in common however - they all reward good EXP for the level they are designed for. You will do many of these quests on route to the level cap.
These are your basic filler quests, every MMORPG has them. You get given a task by an NPC and then you go out and complete it. Then you return for your reward. The quest may involve killing X amount of a certain creature, interacting with objects within the world to obtain items for the NPC or simply heading over to an NPC to speak to them and gather information.
The rewards for these kinds of quests are usually equipment, gil, potions and such. Usually you can choose from a selection. But the main reason you will do these is for the EXP. You will do a lot of them and usually the end point of a quest is the start point for a new quest.
Main Scenario Quests
The main scenario is where the game shines. It's a Final Fantasy game so a well designed and engaging main scenario is a must have. No other MMORPGs focus on story as much as those in the Final Fantasy series, and like with XI this game will have a lot in the way of story.
The main scenario is there to bring the world to life, to explore what happened between the end of the Sixth Astral Era and now, to explore current plot lines within the game and what is happening in the continent of Eorzea. This page isn't for spoilers so we're not saying any more. The main scenario comes with voice acting, cut scenes and lots of fun but difficult battles for you to enjoy.
Rewards for the main scenario include equipment, a large chunk of EXP and the unlocking of game features, dungeons, primal battles and more. It serves as a foundation for everything within the game and as you progress through it you will have more and more options.
Class quests are designed to give you background information on your class as well as a bit story related to the class. They will typically reward a basic weapon or tool related to your class and some EXP. The level 15 and 30 class quests will also reward a useful ability that your class can use. It is essential to do your class quests just for these abilities.
It is a good idea to do the level 1 class quest on every class even if you do not plan to level it. This is because for each class you complete the first class on you will be rewarded with a gear set. Gear sets are used for storing equipment templates for fast class switching. The first class quest takes around a minute and you do not even leave the guild room.
Similar to class quests the job classes are to help you progress your job. They are even more important than class quests in that every job quest will reward you with an ability. So if you don't do these then your job will be useless. You will also obtain artifact armour
as a reward for the quests.
Some of the job quests are designed for solo players while the higher level ones will require a full party. At least this is how it worked in 1.0. They were fun fights with plenty story behind them.
Grand Company Quests
Grand Company quests are given to you by the Immortal Flames, Twin Adder and the Maelstrom. You can only be a member of one company at a time however. These quests are a bit more indepth than the fetch quests and are generally story related.
By completing the Grand Company quests you can apply for promotions. This increases your rank within the Grand Company and gives access to more equipment and items from this company. These items are purchased with company seals, which are rewards from company quests and F.A.T.E.