i have a question that’s sort of hard to describe



Not quite correct I am afraid. Bxc5 means B captures opponents piece on c5. If the opponent has no piece on c5 to begin with the notation is simply Bc5.
It gets slightly more complicated when two pieces could both move to the destination square. Say both of white's Rooks on their starting squares are capable of moving to e1. The notation is then Rae1 or Rhe1 depending which one is moved.

https://www.chess.com/terms/chess-notation

I have a very strong feeling that the OP is not talking about chess notation. Because chess notation is so obvious, "bishop to c5" as "Bc5" would never be described as "a short string of letters and numbers". Maybe he is talking about FEN or something like that.