Basic information for those wishing to get started in World of Warcraft. This is not meant to be exhaustive, merely to cover the most basic info. This information is valid for the Legion Expansion.
Some basic terms that are useful to understand (this is not meant to be exhaustive):
There are two playable factions: the Alliance and the Horde.
There are six races for the Alliance: Humans, Dwarves, Night Elves, Gnomes, Draenei, and Worgen.
There are six races for the Horde: Orcs, Trolls, Tauren, Forsaken (Undead), Blood Elves, and Goblins.
A seventh race, Pandaren, can choose to join either the Alliance or the Horde. The choice is made early on and is irrevocable. (within the game. You can always pay for a faction/race change and simply choose a Pandaren of the opposite faction if you *really* want.)
The faction you choose dictates who you can communicate and group with. Alliance races cannot group or talk with Horde races.
There are twelve classes to choose from: Death Knight, Demon Hunter, Druid, Hunter, Mage, Monk, Paladin, Priest, Rogue, Shaman, Warlock, and Warrior.
Certain classes are limited to certain races, while others can be played by any race.
There are three primary roles characters fulfill: Tank, Healer, and Damage. Some classes can fulfill multiple roles through their specialization (spec), while others just provide different styles of fulfilling one or more roles.
If you want to tank, you can be a:
If you want to heal, you can be a:
If you want to focus on damage, you can be a:
There are four armor types: Cloth, Leather, Mail, and Plate.
Classes no longer start start on a different armor type, and should use their correct armor type from the start.
Classes that can wear multiple armor types get a passive bonus at level 50 for wearing their highest armor type, so there is no reason to seek armor of a lower quality.
You wear Cloth if you are a:
You wear Leather if you are a:
You wear Mail if you are a:
You wear Plate if you are a:
As with armor, your ability to equip a weapon doesn't automatically indicate that you should equip that weapon. Right now, only Hunters (except Survival) should wield a bow in combat, because only Hunters will have a full set of attacks to take advantage of using a bow. For everyone else, look at what your primary stats are, your passive abilities, racials, and what you can equip. That will tell you whether you should be dual-wielding (i.e., Rogues, Fury Warriors) using a single 2-handed weapon (i.e, Feral Druids, Retribution Paladins), or using a 1-handed weapon and shield (i.e. Protection Warriors, Protection Paladins).
There are 4 attributes: Strength, Stamina, Agility, and Intellect. Strength, Agility, and Intellect will increase stats that increase your damage (Attack Power for the first two, Spell Power for the last). Strength will increase Parry rating for strength users. Agility will increase Dodge rating for agility users. Stamina is a given stat on pretty much any armor or weapon you come across.
You will be getting Strength on your gear if you are a:
Notice how right now, all the classes that make use of Strength also wear plate.
You will be getting Agility on your gear if you are a:
Agility classes will be wearing leather or mail.
You will be getting Intellect on your gear if you are a:
Intellect users span the entire spectrum of armor.
The secondary stats are Critical Strike (Crit), Haste, Mastery, and Versatility.
Each character will require its secondary stats in different degrees. For example, one spec may favor Mastery primarily, while another might favor Haste.
An item has a chance to be created with a tertiary stat that, while not a major game-changer, can help in the strength of your character. These are Avoidance, Indestructible, Leech, and Speed.
Artifacts are weapons for each spec that will grow in power with you throughout the expansion. Each spec of each class has its own artifact. You will gain Artifact Power through much of the content in Legion. Artifacts have their own set of traits. You can also unlock appearances through various types of gameplay, and some are hidden, requiring varying degrees of difficulty to obtain.
There are 6 different qualities of items represented by different colors: Poor (grey), Common (white), Uncommon (green), Rare (blue), Epic (purple), and Legendary (orange). The are rewarded for virtually any type of content.
On drop, items have a chance to upgrade, in increments of 5 item levels, from its base item level to a certain cap (up to +15 levels higher than the current mythic item level). Items upgraded up to +10 base item level are called Warforged. Items upgrades 15 item levels or more are called Titanforged. The item will attempt to upgrade in these increments until it fails, or until the cap is reached. So, while there is a chance you could get a mythic level (or better) item from questing or mobs out in the world, the chance is not high.
There will also be a chance to get legendary items in Legion content, which will give certain benefits related to the classes/specs they're for.
There are also class-specific item sets available in raids. These provide a unique look and extra benefits for the intended wearers.
All players now have a wardrobe. Whenever a character has an item bound to him/her, that character gains the appearance of that item to apply to their current gear, so long as that item is equipable and of an item type meant for that character. For example, a Warrior can not gain appearances for cloth gear, but can gain the appearances of plate gear. Paladins cannot gain appearances for Staves, but Mages can.
Once you have an appearance, you can go to a Transmogrifier to put that appearance on your gear, and also can save sets of appearances to apply en masse to new gear when you get upgrades.
Most companion pets are also Battle Pets. You can fight other battle pets with them, level them to 25, upgrade them to rare quality, and collect them. Thou must obtainest them all.