There is no evidence to suggest that inhaling heated or humidified prevents or cures the Coronavirus. This claim is baseless.
Steam inhalation is one of the widely used home remedies to soothe and open the nasal passages and get relief from the symptoms of a cold. Steam therapy can help thin mucus as a supplemental course of action to give some relief when grappling a cold or flu.
World Health Organization (WHO) does not suggest steam therapy with any ingredient as a cure for the coronavirus. It also says that taking a hot shower and exposing oneself to a temperature higher than a 25C degree does not prevent or cure COVID-19. It also tells COVID-19 can be transmitted in areas with a hot and humid climate.
So the claim that inhaling steam from the hot water will kill coronavirus is false and baseless.
The COVID-19 pandemic has given rise to a lot of potentially dangerous misinformation. For reliable advice on COVID-19 including symptoms, prevention and available treatment, please refer to the World Health Organisation or your national healthcare authority.