Artificial satellites are built by various space agencies and are sent into space above Earth's surface. These are of two types. Geosynchronous satellites and polar satellites.
Geosynchronous or geostationary satellites are placed around 30,000 km higher above surface of Earth. The satellites have the same orbital angular speed around Earth as the angular speed of Earth in rotation about itself. So the satellite placed in the orbit remains stationary wrt the satellite control center.
These satellites are used for telecommunications and television transmission purposes. Three satellites are placed at equal distances around the Earth to be able to transmit or receive signals from any part of the world to any other.
These satellites are costlier, and have about 3 years to 5 years life. They derive energy from the Solar panels which receive sun light and store in a battery. These satellites are monitored from the Master control facility and satellite control centers.
There are another kind of artificial satellites called polar satellites. These are low orbit satellites in orbits of around 800 to 900 km above Earth. These satellites orbit Earth continuously around 10 times a day. These satellites send data from scanning of Earth's surface and the atmosphere (and clouds). These images are processed for weather predictions. These artificial satellites have less visibility between the times they are horizon. These are used for crop monitoring, cyclone monitoring, border monitoring, searching in oceans for ships or Aircrafts etc.
These polar satellites are not so expensive and have lesser life as compared to the geostationary.