There a 3 main style of grips for paddles - Rubber Grips, Wrap Grips (Replacement Grips), and Overwrap Grips.
Rubber Grips are the most durable and usually can last the life of the paddle. Pickleball paddles dont come with a factory rubber grip, the wrap grip must be replaced. At PaddleballGalaxy you can have a Python Rubber Pickleball Grip installed when you purchase a new paddle, they come in 16 color to match about any paddle. When using a rubber grip it is best to also use a Leather Pickleball Glove. A rubber grip and leather glove combination creates a better bond between your hand and your paddle than any wrap grip can give you.
Wrap Grips are what most pickleball paddle come with, they are usualy a padded grip with some thickness to them that provides comfort and in some cases mositure wicking to control sweaty hands. Wrap grips wear over time and need to be relpaced.
Overwrap Grips are thin grips that go over the top of wrap grips. They are commonly used to reduce the wear of the Wrap Grip under them and must be replaced fairly often. They are very easy to replace and are cheaper than any other grip type. They can also be used to build up the thickness of a grip if the size of the paddle grip is too small for your hand. 1 wrap of an ovegrip usually builds up the thickness by 1/6".