How to get a palidin mount

Paladin trainer when your high enough lvl to get it

Your Paladin trainer will sell it to you like a spell. You get the slower one at level 20, and the faster one at level 40.

You also have to have bought mount training from the mount training vendor. They're in each race's starting area. Ask a guard in that zone, or ask your friends in guild chat.

Good luck,
-Nih