Powell arrives from Crewe Alexandra.
"He's a fine prospect. I've seen a few clips of him and watched a few games back home," Ferdinand told The Sun.
"He has an unpredictable style and can play off-the-cuff. He can pull things out the hat that you don't expect.
"We've not really seen as much as we would have liked in training as we're just doing a lot of small-sided work at the moment, but he has a great first touch and he's not afraid.
"He seems a confident lad and he's integrated straight into the squad.
"For a young lad, to come into an environment like Manchester United from a lower league club, you have to say he walked in with his shoulders back as if he's meant to be here.
"And that's a great start to his career here."