Eu estou, você está, ele/ela está, nós estamos, vós estais (very hardly used in Brazilian Portuguese), eles/elas estão.
Only by knowing each one's conjugation, you will know the difference between "Onde estou? - Where am I?" and "Onde estamos? - Where are we?".
The one who is weird to hide the pronoun is the "Ele/Ela", because the other person will not understand who you are metioning her, him or a thing, so it is used "Onde ele/ela está?" or "Onde está ele/ela?.