Where do you get a pet on World of Warcraft

Non-Combat Pets Non-combat pets (companions) can usually be bought at the Auction House. Sometimes vendors will sell one or two extremely common pets for cheap. Blizzard will usually give some kind of unique pet on their anniversaries and conventions. You can also get pets from the Trading Card Game to use in-game.
 Combat PetsHunters: Hunters start using pets at level 10, and there is a quest that you must complete in order to tame beasts to serve as your pet. You have to feed hunter pets to make them happy. The happier they are, the more damage they do. Hunter pets have talent points to customize their attack style starting at level 20, and gain levels just like a player, getting a percent of each experience gain from the hunter. Hunter pets are unique in that they are the only combat pet that you can rename.

Warlocks: Warlocks use demons to serve as their pet. The main demons are (in order of when you can get them):
Imp: Throws fireballs -- DPS type of pet

• Voidwalker: Does Melee -- Tanking pet. Very good at holding aggro.
• Succubus: Does Melee -- DPS type of pet
• Felhunter: Does Melee -- DPS, can remove magical effects from party members.
• FelGuard: Does Melee -- The Ultimate Tanking Demon (but you have to spend points in the demo tree to get it.

Mage, Priest, Death Knight: Mages, Priests, and Death Knights can access a pseudo-pet via talents. Mages have a Water Elemental in the Frost tree and it can be made a permanent pet through a glyph. Priests get access to the Shadowfiend. It does not last very long. Death Knights can access a ghoul to fight for them for about a minute, however, UNHOLY Death Knights can make it a permanent pet via talent points.