Question about reading music for the piano?

I am teaching myself to read music for the piano, and I'm very, very new to this. I am having some trouble understanding this: Let's say I need to play an F....can I play the same key (octave) regardless of whether it is the F near the bottom of the lines or near the top? (ie; the F in "FACE" versus te F in "Every Good Boy Does Fine"). Sorry, I have no idea what the "lines" are called, this was the best way I could explain it!