You can select from 2 types of controls, Action Type or Control Type.
Action Type is recommended for fans of the Metal Gear Solid series.
Shooter Type is recommended for fans of first-person shooters (FPS).
Action Type is the default control type and the one referenced by default when mentioning controls throughout our resources.
You can change the control type using [OPTIONS] on the Pause Menu.
On Vehicles
An action icon appears when you approach the driver's seat of vehicles that you can control. To get into the vehicle, press the Action button while the icon is displayed. The controls change while you are driving a vehicle, and will have a different configuration based on Action vs Shooter Type.
Horseback - The Phantom Pain Only
Approach your horse and the "mount horse" action icon will appear.
Press the Action button to mount your horse.
Commands will change while you are on your horse and will have a different configuration based on Action vs Shooter Type.
Using Walker Gear - The Phantom Pain Only
The Walker Gear is a man-sized bipedal weapons platform.
Approach a Walker Gear and the "pilot Walker Gear" action icon will appear.
To pilot the Walker Gear, press the Action button while the icon is displayed.
The controls change while you are piloting the Walker Gear, and will have a different configuration based on Action vs Shooter Type.