Question: does a pawn have to capture a piece

Answer: No, Unlike the other pieces, pawns cannot move backwards. Normally a pawn moves by advancing a single square, but the first time a pawn moves, it has the option of advancing two squares. Pawns may not use the initial two-square advance to jump over an occupied square, or to capture. Any piece immediately in front of a pawn, friend or foe, blocks its advance. In the diagram, the pawn on c4 can move to c5, while the pawn on e2 can move to either e3 or e4.