A mount attaches your antenna to a cable, that in turn connects to your mobile radio. Surface mount antennas are permanent and require a hole to be drilled in your vehicle. Magnetic mounts can be easily removed. The cable can be seen with a magnetic mount, where it is hidden on a surface mount.
Since the cable is attached to the radio, it's important you get the correct connector type. Different radio brands use different connector types. Check with the radio manufacturer to determine the correct connector type. All Icom radios use PL259 type. Most Motorola radios use Mini-U type.