Motors and Servos may sound like they do the same thing but have different applications.
Movement: Spins clockwise and counter-clockwise
Applications:
Types:
Movement: Spins clockwise and counter-clockwise with precision
Applications:
Types:
Closed-Loop: Limited range of motion usually 90 or 180 degrees but can precisely control the position of the servo
Open-Loop: Unlimited range of motion but can precisely control the direction and speed but not the position
Two wires
red = Power
black = Ground
To make a motor spin, send power through the red wire and ground the black wire. If you want to reverse the spin then send power through the black wire and ground the red wire.
Three wires
red = Power
black = Ground
white/orange = Control
To control a servo you use something called PWM (Pulse-Width Modulation).