How do you get champion's seal in World of Warcraft?

Answer 1

Once you become level 79, you will receive an email from Mariel Trueheart, a crusader at the Argent Tournament. When you go there (it is situated at the Northern coast of Icecrown) you will be given a few basic quests (discovering that the Black Knight isn't who he claims he is, learning to ride a tournament mount, and so on).

Once these basic quests are done, you will get daily quests from your capital city's representative in the tent at the North. Each will offer one or two aspirant's seals. Once you have the full tally, you are ready to begin championing that city and continue with the questlines.

Answer 2

If Im thinking of the correct place there is an area in icecrown or something from the lich king expansion that's like way in the upper right corner and you can do the dungeon in that area and the raid and daily quests I believe.