Each Starlink satellite weighs 227 kilograms and is roughly the size of a table.
Rather than sending internet signals through electric cables, which must be physically laid down to reach far-flung places, satellite internet works by beaming information through the vacuum of space, where it travels 47% faster than in fiber-optic cable.
Current satellite internet works using large spacecraft that orbit 35,786 km above a particular spot on the Earth. But at that distance, there are generally significant time delays in sending and receiving data. By being closer to our planet and networking together, Starlink’s satellites are meant to carry large amounts of information rapidly to any point on Earth, even over the oceans and in extremely hard-to-reach places where fiber-optic cables would be expensive to lay down. 

While SpaceX eventually hopes to have as many as 12,000 satellites in this megaconstellation, the size and scale of the project have flustered astronomers and amateur skywatchers, who fear that the bright, orbiting objects will interfere with observations of the universe. 
Elon Musk's initial estimate of the number of satellites soon grew, as he hoped to capture a part of the estimated $1 trillion worldwide internet connectivity market to help achieve his Mars colonization vision. The U.S. Federal Communications Commission (FCC) has granted SpaceX permission to fly 12,000 satellites and perhaps as many as 30,000 eventually.
To put that into perspective, only about 2,000 artificial satellites currently orbit Earth, and only 9,000 have ever been launched in all of history.
The first 60 Starlink satellites were launched on May 23, 2019, aboard a SpaceX Falcon 9 rocket. The satellites successfully reached their operational altitude of 550 kilometers — low enough to get pulled down to Earth by atmospheric drag in a few years so that they don't become space junk once they die.