Help Requested: How to Cover Up Edges?

Hello guys. So I have a psd file that has been worked by a graphic designer and I always take this layer (the one in the picture attached) from his psd file, and I noticed that during my work I need it so much so that I can cover the edges of my pen tool cut layers so I put one of those on every edge. How can I make a similar layer? And how can I lets say make a cloudy one with low opacity from 1 end and full opacity on the other end just like this photo. And Thank u

See original post by Hani T