The motor on a drone with a connected propeller is what provides thrust to elevate the drone into the air. Drone motors are inexpensive, small, lightweight, and powerful. The motors are either brushed or brushless, and the construction of the motor determines this. The most efficient motors are of the brushless variety.
Choosing the right motor for your drone depends on a multitude of factors. First, you look at the frame size of your drone, the diameter of the propeller you will be using. Follow this up with the stator size and KV of the desired motor. Look at the weight, efficiency, power, and torque desired in your drone build, and lastly, look at the ESC you are going to use and if it will provide enough amperage for the motor run at its optimal performance.