Starlink is a constellation of eventually 42,000 satellites that are placed in low Earth orbit at an altitude of just 550 km. The satellites (will in future) use laser links to send packets of information between themselves and use microwave signals to send and receive from the ground antennas.
The use of such low level satellites (instead of the traditional geostationary communication satellites orbiting at an altitude of 36,000 km) reduces the transmission times significantly, and should result in faster signals than even a transatlantic fibre optic cable.
They have an inclination of 53 degrees, so that means as long as you are not close to the Arctic or Antarctic regions, you will have the same coverage anywhere on the planet.
Falcon 9 payload fairing showing the “IKEA flatpack” stacking arrangement of 60 Starlink satellites ready for launch.
At present there are “only” 482 satellites deployed, but SpaceX are planning to launch 120 every month (60 satellites per Falcon 9 launch every two weeks) for the next decade in order to build the fleet (which will need constant renewal as they are designed to have a limited lifespan). They expect to start limited service by the end of the year, which will progressively grow as the number of satellites expands.