Modify > Convert > Subdiv to Polygons

Tessellation Method

Select one of the following tessellation methods.

Uniform: Uniform tessellation produces a polygon with an equal number of faces for each of the subdivision surface’s base mesh faces (faces at level 0).
Polygon Count: Polygon Count is the same method as Uniform, but with a threshold value beyond which the conversion fails. Use Maximum Number Polygons to set this value. The resulting polygon will have at most this many polygons, but there is no guarantee that the number will be exact.
Adaptive: Adaptive tessellation produces a polygon with an equal number of faces for each of the finest level faces on the subdivision surface. The more refinement you’ve made to a region of the subdivision surface, the more faces the resulting polygon will have for that same region. Use Divisions Per Face to control the number of faces produced for each finest level face.
Vertices: Produces a polygon that matches the vertices on the subdivision surface. The polygon matches vertices to the level specified in the Level option.

Level: If you are using the Uniform option, set the level to determine how many faces are to be used in the tessellation. For example, if Level is 3, the faces at level 3 are used in the tessellation.
Divisions Per Face: Specify how many times each face should be divided when performing a Uniform or Adaptive tessellation. Increasing this value smooths the polygonal surface.
Maximum Number Polygons: Sets the threshold number of polygons used by Polygon Count tessellation.

Original Object

Select what you want done with the original selected object after tessellation. Use the Original Object settings to maintain a form of construction history, as these override the global construction history settings.

Replace: The subdivision surface is deleted when the polygonal surface is created. This is the default.
Hide: Hide keeps the subdivision surface, but hides it when the polygonal surface is created. The source object can be viewed in the Hypergraph and Outliner (select Input and Output Connections), and made visible in the modeling view by using Display > Show > Show Selection or All.
Show: Show keeps the subdivision surface and keeps it visible in the modeling view.

Share UVs: With this option turned on, the resulting polygon will maintain existing UV mesh borders. If this option is off, UV borders are created for each polygonal face.