You can edit a player by tapping on their name which should bring you to the player screen. Then in the menu bar you should see "Editor". If you tap on that you'll be able to change many details.
You can't change their team this way, to change a player's team I think the easiest way is to apply to be the GM of their org, then trade them to the team you want them on in exchange for peanuts.
Hope that helps!
