I finished the main quest and beat Alduin, and now I can call Odahviing on request. But looking at my call dragon shout, its says I can call three different types of dragons? How do you change the shout to do so.

Secondly how do you ride the dragons?

I don't know about calling three types of dragons but to ride dragons you need the Dragonborn dlc.

Edit: The Call Dragon shout is to summon Odahviing, you summon him to aid you in battle. I don't think he's rideable again...

Wrong section and what platform? And do you have dlc?