This is technical for most, but a necessary skill if you want to lift big weights in the clean and jerk. The skill of readjusting your grip in the front rack position after the clean but before the jerk will make a big difference.
For the vast majority of us, we catch the squat clean in an open grip–or a grip with 1-2 fingers off the bar. This is fine, but presents an issue when it’s time to jerk the weight overhead. The proper hand position for the jerk requires that all fingers get back around the bar.
The preferred technique for most weightlifters is popping the bar off the shoulders when coming up from the squat. Here is a drill that you can practice in order to eventually get the mechanics of this skill down.