Even the most rudimentary sentences usually have a subject, a verb and a direct object--a person or thing that directly receives the action of the verb.
Ella bebe el café. Sub. V. D.O.
She drinks the coffee. Sub. V. D.O.
The subject performing the action is Ella, the action is the verb bebe, and the direct object is el café, which answers the question, What is she drinking? All direct objects answer the question whom? or what? about the subject's actions.