Corona viruses are a large group of viruses many of which cause no or minor illnesses, like the common cold. Some cause illness in people, and others only infect animals. Usually these infections do not cross over from animals to people.
On rare occasions, coronaviruses that infect animals “change” and develop the ability to infect people. This has occurred with Middle East Respiratory Syndrome (MERS) and Severe Acute Respiratory Syndrome (SARS) where the causative viruses were probably initially infections of bats. The new (novel) coronavirus was probably also an infection of bats but is now able to infect people. The new (novel) coronavirus is officially called Coronavirus Disease-2019 or COVID-19 (because it was first detected in 2019).
Read more: https://covid19.who.int/.