What is the differences between passive voice and active voice?

Firstly, in an active sentence (voice), the subject is performing the action of the verb. For example, Susana tocó el piano de Ana. (Susana played Ana's piano)  In this context, 'Susana' is the subject of the voice, is the person who is performing the action of the verb: 'play'. The subjects of an active voice is called AGENTS.  On the other hand, in the passive context, the subject receives the action, is acted upon by the agent. Using the same example as above: El piano de Ana fue tocado por Susana. (Ana's piano was played by Susana) Here, Ana's piano receives the action performed by Susana (agent) There are 2 types of passive voice constructions:  the most common one is what I have used in the examples mentioned before, that is, using verb SER (conjugate same as the active tense)+ Past Participle of the verb  (por + agent) and the other one is: SE + 3rd person of verb (singular or plural depending on the subject)