When it comes to holding a guitar pick, the bad news is that there is no single right way to do it. The good news is that there are lots of right ways.
As with everything in picking technique, this multiplicity of correctness is actually the greatest challenge. With so many combinations of contact points and orientations that actually do work, it can be hard to know which one to choose.
To make matters more confusing, these options aren’t totally arbitrary. There is a relationship between pick grip and other aspects of your setup, like wrist orientation, forearm orientation, anchor points, and picking motion, which explains why certain combinations of these elements are often found together in the techniques of expert players.
That’s why the best way to understand grip is to understand each of its component parts, and how they interact with your technique as a whole. This way, no matter which variation you use, you’ll understand why and how it works.