For the jab I see on videos and from others a few different techniques for the jab punch (leading arm facing the opponent).
There is one style which lifts slightly the forward foot while the arm pulls slightly back before pushing, and as the arm goes forward the forward foot makes a small step forward, and the punch lands at approximately the same as the foot grips the floor again. The whole body has only slightly turned in the direction of the punch. To get fast multiple punches the forward foot hardly touches till the jabs are finished as the step never completes.
The second style is where the forward foot does not displace but has a larger turning movement with the body for the jab. The forward foot at an angle of initially about 30 degrees turned away from the opponent becomes larger to about 45-60 degrees and the shoulders are almost completely in line with the punch.
The third places very little emphasis on the legs moving but calls for a dance like grip to support the shoulder's momentum pushing the arm. Recoiling the arm is fast here although the acceleration feels like there is a delay requiring my hips to support the body twist.
Is either one the correct way? or do they serve a different purpose depending on the distance of the opponent and the strategy to place yourself in the opponent's space? or due to the speed/strength trade offs of each punch?
Or is it a matter of personal taste. The third gives me the greatest speed as having the feet in place I recoil the arm without losing balance.