We use personal pronouns to talk about people without naming them. They substitute the noun and are usually used for emphasis or to avoid confusion. Besides the commonly used yo, tú, él, ella, nosotros, Uds, ellos (as), there are other personal pronouns. These are indirect object pronouns, direct object pronouns, and reflexive pronouns.

Indirect Object Pronouns
(me,te,le,nos,os,les)
Me dio todo lo que tenía.
He gave me everything he had.

Le di los boletos a Juan.
I gave him the tickets (Juan).

Direct Object Pronouns
(me,te,lo,la,nos,os,los,las)

Estaba estudiando cuando me llamaste.
I was studying when you called me.

Él ha adorado a su novia desde el primer día que la vio.
He's adored his girlfriend since the first day he saw her.

Reflexive Pronouns
(me,te,se,nos,os)

Yo me lavo la boca.
I rinse my mouth.

Se quita el sombrero.
He takes his hat off.