Having knowledge about pawn endgames is also useful when there are more pieces on the board. If you know that you can achieve a winning pawn endgame by exchanging pieces, you can steer towards that. The same applies the other way around. If you are not in a good position, but you see that you can reach a drawn pawn endgame, then it is beneficial to exchange pieces.
Exchanging pieces to move to a favorable endgame is called simplification.
In the first example we see that white simplifies into a winning pawn endgame by exchanging rooks.
In example 2, black saves half a point by fleeing into a king and pawn versus king endgame that is a draw.
What do you have to do?
Simplify into a winning pawn endgame.
Are you defending? Then simplify into a pawn endgame that you can draw.