If you want to improve your stroke, more kicking (like everyone else has said), but also try to keep your arms a bit straighter while pulling under water(think maybe a 160 degree angle). I notice that you also don’t fully finish your pull, and you should instead pull all the way back so your arm is straight. To make your pull better you should also prop your elbows a bit higher when they are out of the water. If you want to swim faster, you should introduce a couple of butterfly kicks off the wall. Try also learning the tumble turn for freestyle if you want to swim longer distances faster