Where should you be entering your hand into the water?
If you are entering the water beside or just in front of the head you are likely to be either spearing too deep into the water loosing the front end of your catch and pull-through or alternatively as you extend your arm forward you drop your elbow below the wrist inadvertently slowing yourself down as you put the brakes on (below picture).
However at the other end of the spectrum is reaching as far forward as you can before entering the water (below photo). A key component of an efficient freestyle catch & pull through is maintaining the elbow higher than the wrist and wrist higher than the fingertips. When you overreach above the water you have a high chance of dropping the elbow and simply pushing down in the water with the straight arm. This gives you lift through the front of the body forcing the hips and legs down so not ideal.
So somewhere in-between these 2 is the right place. I recommend a position of anywhere between the elbow and wrist of the extended arm out front with the main thing to remember, the finger tips enter before the wrist and wrist before the elbow. This provides a much better chance of setting yourself up for a good catch and pull through.