Here are the translation of each pronoun:
yo - I/me
tú - you
él - him/he
ella -she/her
usted - you formal
nosotros -us/we (of either a solely male population or a male and female population)
nosotras - us/we (of a solely female population)
ellos - them (of either a solely male population or a male and female population)
ellas - them (of a solely female population)
ustedes - you all formal (so you have to be talking about at least 2 people)
Since Eva is a singular person and also female you would use "ella" to talk ABOUT her
Hope this helped!
