What is Transmogrification?
The act of changing an item into a different form or appearance, but keeping the original stats.
Where is it?
Go to any of the Eternal Gateways around the server.
Right click the Eternal Gateway and go to "Mall" and then "Event Chamber".
The NPC is named "Zedron the Impatient" He is straight in front of the Gateway in the Event Chamber, along with the Consigliere and Daily Quest Giver.
How do you use it?
Make sure you have the item you want to change the appearance of equipped.
Next, make sure you have some "Transmogrification Tokens", these are randomly given out at the end of any battleground or arena match, and the item you want the appearance of in your bag. Then right click "Zedron the Impatient" and go to "Transmogrify Items".
Next choose the item slot from the menu that you want to change the appearance of.
For an example, this is how to transmogrify your weapon. First select the "Main Hand" option and a new menu will open. This is where your compatible items will appear if they are in you bag. In this case it is Sulfuras.
Once you select the item. In this case Sulfurus. A box will appear telling you that it requires "Transmogrification Tokens" to complete this action. Simply hit "Accept" and your item will now be transmogrified!
The end result!
If it all worked properly your item should look differently but still have the same stats and name as your real item.
To transmogrify a weapon (Main Hand, Off Hand, Ranged) it costs 3 "Transmogrification Tokens".
To transmogrify any other piece of gear it costs 1 "Transmogrification Token".
You may only transmog similar armor types, for example plate > plate. The transmog compatibility for weapons is limited to same the same weapon type; for example sword > sword, bow > bow, etc. However if you achieve 2200 arena rating in 2v2, 3v3, 5v5 or gain 30,000 honorable kills then you unlock the following:
One-handed sword, mace, axe > One-handed sword, mace, axe
Two-handed sword, mace, axe > Two-handed sword, mace, axe
Polearm > Staff
Bow > Crossbow
There are also additional features such as transmogrifying your weapon enchants and also purchasing sets of legacy gear to spice up your character's look. These options can be found in Zedron's main menu.