Handwashing with soap removes germs from hands. This helps prevent acquiring and spreading infections and virusesbecause:

Without realising we frequently touch their eyes, nose, and mouth. The germs find an easy entry into our body through the eyes, nose and mouth.
Unwashed hands can get into foods and drinks as they are prepared and consumed
Such germs and viruses can multiply in some types of foods or drinks
Unwashed hands can be transferred pathogens to objects, like door handles, handrails, table tops and toys when then transferred are transferred to another person’s hands.
Removing germs through handwashing therefore helps prevent many illneses including diarrhoea and respiratory infections and may even help prevent skin and eye infections.