Freestyle Hand Entry or PlacementI like the swimmer's hand to enter the water directly on a line drawn from the swimmer's side, up and through the shoulder and ending at your destination. Not wider than that, not way out to the side; not narrow, not above the head. Just in line with the shoulder. This puts the hand in position that allows you to just flex the wrist a bit, then the elbow, and drop right into a good catch position. No moving the hand left or right, just swinging it down.
I want the arm slightly bent at the elbow as the hand enters the water. That means the hand hits the water almost the full length of the forearm ahead of the swimmer. Some swimmers enter the water with a very bent elbow, with the aim of sliding the hand and arm forward, through the water, to an extended position. I prefer that extended position to be almost established before the hand goes in the water. I think that is less drag and allows for a faster swim rhythm. By keeping the elbow slightly bent on the entry, the movement to the catch position should be easier.
I do not worry about the swimmer splashing or smashing the hand on the entry. What happens will happen, and unless the swimmers is trying to make a big splash, there is usually not enough to worry about. One key is to keep the hand flat to tipped slightly down on the entry vs. tipped up. Don't let the hand enter palm first, fingers up, that pushes a lot of water forward. Never "show" your palm to your destination. Putting your palm forward, fingertips up, is like making a STOP signal, and it can do just that, creating a lot of extra drag and slowing you down for no reason.
Hand OrientationI see a lot of swimmers entering the water thumb first I always wonder why. What is the advantage to doing that kind of entry? I think it might make less splash, but I don't think that is very important - swimming is not diving, no one is judged on the splash.
A swimmer's hand should enter the water flat to slighty rotated thumb up. The pinky, ring, and middle finger should enter first, or all four fingers first, almost a flat hand entry. The thumb should be going in last (if you have a lot of shoulder problems, you might make a major modification and enter with a karate chop, pinky first, and then rotate to flat after the entry, but I understand the reason behind this, even if it looks odd).
Now What?You have extended your arm over the water, you have a slight elbow bend, your hand is above the water in line with your shoulder and the destination. Your hand is flight or slight tipped downward. YOur hand enters the water, slides forward the remaining 1-2 inches to reach full arm extension. Now what? Flex the wrist, tip the fingers down slightly, followed by tipping the whole forearm down. Keep the elbow up near the surface, lower the forearm and hand down under it; my favorite saying for this is draw a line from elbow through fingertips, that line points straight down. Once you reach this position, you are in the catch position or the early vertical forearm (EVF) position. Now apply pressure on the water from your fingertips, through your wrist, all the way up your forearm. Push the water backward toward your feet. Whoosh! Good entry, good catch! Repeat, repeat, repeat. Looking for some basic ides on swimming freestyle? Check out the How to Swim Freestyle video.