This is the 1517th most frequent Spanish word.
ella
"She" or "her" (third-person singular feminine pronoun).
The word 'ella' is used here as a subject pronoun referring to a specific third-person singular female individual.
Ella es ingeniera y trabaja en una empresa internacional.
She is an engineer and works at an international company.
The word 'ella' is used here as an object pronoun to denote the person seen by the subject, corresponding to the third-person singular female.
Vi a ella en el parque hablando con sus amigos.
I saw her in the park talking with her friends.
In this sentence, 'ella' is used as the indirect object of the verb, emphasized to indicate the person who loves an activity.