What kind of saw can a woman use to cut brances from trees or schrubs?

There are too many variables to know how to answer this. How big a branch do you want to cut? How high are the tree branches? If beyond your reach, do you want to cut the branches while standing on the ground or are you willing to use a ladder? Are you a frail woman or an Amazon?

The simplest saw for this is a manual saw called a "Pruning Saw." A more versatile saw is an electric chain saw.