Soaking the potatoes helps draw the starch out, stops them from sticking together, and all-in-all creates perfectly crisp fries.
You do not have to peel the potatoes before slicing, however, you can peel them if that is how you prefer them.
The two best types of potatoes for french fries are Russet and Yukon gold potatoes. Yukon gold will produce a soft yet crunchy fry and russet potatoes give more of a classic french fry taste. You may know Russet potatoes as Idaho or Yukon's as yellow. Do not use a waxy variety like fingerlings or red potatoes