If the outdoor fire pit will likely be set up on the ground, then it be considered a built-in one. Having a built-in fire pit will mean that you ‘must’ have it installed on a fixed location. Either on the ground, or perhaps an outdoor wall or post. You could also use a fixed concrete made to hold your outdoor fire pit. Outdoor rings or perhaps some kind of burners could be of different styles as well. The round one is the ring, of course, if you wish to have other styles, then you can certainly choose to some other designs for example square, rectangular shape or maybe triangular. Even though, the ring and the round one is advisable in a manner that it distributes the fire evenly.