The main way the disease spreads is through respiratory droplets expelled by someone who is coughing. The risk of catching COVID-19 from someone with no symptoms at all is very low.
www.who.int/news-room/q-a-detail/q-a-coronaviruses#:~:text=The main wa
Asymptomatic transmission
[...] to date, there has been no documented asymptomatic transmission.
Pre-symptomatic transmission
It is important to recognize that pre-symptomatic transmission still requires the virus to be spread via infectious droplets or through touching contaminated surfaces.
Fuente: Coronavirus disease 2019 (COVID-19)
Situation Report – 73
World Health Organization.