While you’re mounted, you have two options. You can either control the mount or allow it to act independently. Intelligent creatures, such as dragons, act independently.
<mark style="background: #FFB86CA6;">You can control a mount only if it has been trained to accept a rider.</mark> Domesticated horses, donkeys, and similar creatures are assumed to have such training.
The [[Initiative]] of a controlled mount changes to match yours when you mount it. It moves as you direct it, and it has only three action options: [[Dash]], [[Disengage]], and [[Dodge]]. A controlled mount can move and act even on the turn that you mount it.
An independent mount retains its place in the initiative order. Bearing a rider puts no restrictions on the actions the mount can take, and it moves and acts as it wishes. It might flee from combat, rush to attack and devour a badly injured foe, or otherwise act against your wishes.
In either case, if the mount provokes an [[Opportunity Attacks|Opportunity Attack]] while you’re on it, the attacker can target you or the mount.