Definition: pronouns in Spanish are used almost, in Spanish they do not need to be expressed since the verb itself will identify the subject, In Spanish, a pronoun is only needed when refering to a third person (singular or plural) for proper identification purposes since it can be a "she", a "he" or even a formal second person singular. In the plural, the verb ending could be referring to a "they" (masculine or feminine) or to "ustedes", a form of the second person plural used by everyone in all the Hispanic countries, except in Spain, where "vosotros" is preferred.
Types of pronouns:
Subject Pronouns
Direct Object Pronouns
Indirect Objects Pronouns
Subject Pronouns: In Spanish, you can say who is speaking or whom somebody is speaking about by the form of the conjugated verb. This is different from English where most all the forms of most verbs are the same: I eat, you eat, we eat, they eat,etc. So in English we have to use the subject pronouns all of the time. But in Spanish, since each form is unique and reveals the subject, we don't have to use the subject pronouns. you may use a subject pronoun or even a name so it is clear whom you are speaking about.