How Can I Change My Title?

[Minotaur]

I wanna change my title, how can I do that I don't know. Can anyone please help me?

[MagicGhost]

I assume you mean in game?
Titles are either given through realm renown ranks which will automatically display your current rank, or you can earn others through rewards such as achievements, monster kills, questing etc. Open your tome of knowledge (press k) and go to the mid tab called Rewards, from there you can select a title if you have any unlocked.

http://warhammeronline.wikia.com/wiki/Title