COVID-19 is primarily transmitted from close (within about 6 feet) person-to-person contact via direct mucous membrane (eyes, nose, mouth) exposure to infectious respiratory droplets produced when an infected person coughs, sneezes, or talks. The infectious droplets are relatively heavy and do not travel far but can get into the mucous membrane of others nearby.
Other potential modes of transmission include spread through inhalation of infectious aerosols, by direct contact with infected bodily fluids, or exposure to contaminated fomites (e.g., door handles, phones, etc.).