Most often, it's in Control Panel>Mouse, but it depends on the driver.
If the user manual doesn't detail it (did you check?) and it isn't in the mouse properties, you'll have to search Control Panel and Settings.
This PC is a laptop? Or a desktop with a keyboard with a touchpad (rather unstandard)? Then it might be in the keyboard settings.
How do I turn off the touch pad on my PC using Windows 10 on new ASUS

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic