Can a user send an email to an external contact?

The external contact is a person who isn't saved as a business contact, lead, opportunity contact, or resource in the sales application. When a salesperson sends an email to an external contact from the context of the Lead, Opportunity, or Account UI of Digital Sales, the sent email appears in the activity feed of the respective object. If the email is sent from a contact record, it's visible in the context of Contact but doesn't appear in the context of other parent objects.