Like anything that rotates, it becomes flattened at the poles and broader at the equator. Here is a diagram showing the main parts of a Kerr, rotating black hole based on general relaticity:

Rotating 'Kerr-type' black holes become flattened, and their internal 'structure' changes in very interesting ways. In non-rotating black holes, the 'event horizon' and the 'surface of infinite gravitational redshift' is the same spherical surface surrounding a point singularity. For a rotating black hole, the event horizon detaches from the infinite redshift surface as you move from the poles to the equator where they have their maximum separation. The singularity becomes a ring in the equatorial plane of the black hole.

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