A cotton variety, designated P07X.8213.RF, the plants and seeds of the cotton variety P07X.8213.RF, methods for producing a cotton plant, either varietal or hybrid, produced by crossing the cotton variety P07X.8213.RF with itself or with another cotton plant, and hybrid cotton seeds and plants produced by crossing the variety P07X.8213.RF with another cotton variety or plant and to methods for producing a cotton plant containing in its genetic material one or more transgenes and to the transgenic cotton plants produced by that method. This disclosure also relates to cotton varieties derived from cotton variety P07X.8213.RF, to methods for producing other cotton varieties derived from cotton variety P07X.8213.RF and to the varieties derived by the use of those methods.