Start with a 7” zipper, any color will do, you could probably get away with using a 5” zipper but the 7” gives you a little more room to play with.
Unzip the zipper so it opens to a V shape.
Fold one side of the zipper around so the teeth are always facing out. The side of the zipper that you would sew into the clothes should come right under where the zipper pull is now. Repeat with the other side, to form a heart shape. This is where you can play with the size of your heart; bigger or smaller.
Pin the ends of where you folded the zipper over
With needle and thread sew the edges down
Trim off the excess zipper and enjoy your heart.
These can be used as necklaces, key chains, and zipper pulls.