The relationship between mass and gravity is described by Einstein's theory of general relativity. According to this theory, mass and gravity are intertwined in a way that mass determines the curvature of spacetime, and this curvature, in turn, influences the motion of objects, creating what we perceive as gravity.
In other words, mass creates a gravitational field around it by curving the fabric of spacetime. The curvature of spacetime determines the paths that objects follow, causing them to move in certain ways under the influence of gravity. The more massive an object is, the stronger its gravitational field and the more pronounced its effects on the surrounding spacetime.
Therefore, we can say that gravity is created by mass. The presence of mass is what generates the gravitational field, and this field is responsible for the gravitational force experienced by other objects.