Which crochet needle is best to use for a beginner?

I started out with an H hook, but, it depends on what project you are going to start with.

The pattern and the yarn affect the hook size, but if you mean for learning, without a specific project in mind, you should work with the size hook you are comfortable with. If you are able, try the knife and pencil holds with different size hooks and see which one "feels" best to you.

I learned using a J hook. I have taught folks who were more comfortable with an N or P, larger hooks. For classes I generally suggest students try an I hook which is a good mid-size hook. I have other hooks available in case there is a problem with that size.

You might find that starting off you crochet either very tightly or very loosely. Tension will stabilize after practice. At that point, you will be better able to determine your "favorite" size.