When do i use "estoy" or "soy"
Yo estoy aqui? or
Yo soy aqui?
2 Answers
You use 'estar' with locations of people or things.
If you'd like to read some more on when to use ser or estar these articles might help.

Ser & Estar Part One - An Introduction for Beginners
Estoy aquí. The personal pronoun is redundant as the verb is conjugated estoy means I am.