Impersonal expressions don’t reference a specific person. Rather, they make reference to people in general and are used to make general statements or questions about what they, one, or you do. That is what makes them impersonal!
You can use impersonal expressions to talk about how things are done according to custom, rule, or general consensus. They are also helpful for asking for directions, finding out how to say things properly, asking what the rules are in a specific place, making general statements, and so on.
Se vive a gusto en Mérida.
Life is good in Merida.
Se come bien en la playa.
You eat well at the beach.
Se duerme mejor con la conciencia tranquila.
One sleeps better with a clear conscience.
Impersonal se constructions are always formed with se + a third person singular verb.
Passive Se
The passive voice is generally used to talk about something that happened to an object without saying who or what carried out the action. only transitive verbs (verbs that require a direct object) are used in passive se constructions. It's very common to use the passive se to talk about inanimate (non-living) nouns. It is not common to refer to people using the passive se.
Se comió la torta.
The cake was eaten.
Se escribió el libro en español.
The book was written in Spanish.
Se alquilan kayaks aquí.
Kayaks are rented here.
Se buscan actores bilingües.
Bilingual actors wanted.
Passive se constructions can be formed with se + a third person singular verb or a a third person plural verb, depending on what is being discussed.
Examples:
Se vende carro usado. (Used car for sale.)
Se venden carros usados. (Used cars for sale.)