I was originally taught to make a triangle with your hands

This however increases the chances of the ball hitting your palm and bouncing off giving you a dropped pass. The only time to do this is if it is a vertical jump ball.
Now Jerry Rice learned to catch underhand by catching bricks from his father; cupping his hands (Underhand)

This way the ball will almost always land in your fingers, making it easy to pull into your body; increasing your catch in traffic and yards after catch.
Just something to look for when evaluating draft prospects.