flatten faces

I had posted this question in modeling, I think maybe I worded my question wrong.
If I extrude ( region ) 2 or more faces on a sphere and I want those faces to be flat as they would be on the side of a subdivided cube . How do I do it?

If I understand your question, you need to select all of the verts at the end of your extrusion and hit the Skey to scale then X,Y or Z key to limit the scaling to a particular axis and then 0 (zero), this will put all the verts on the same plane.

I think he wants to flatten the side of a sphere? Or at least two or more faces after subdivision from the original primitive object.

I think that in that case, the process is basically the same except that after hitting Ekey, hit Enter, then follow the above steps. It is kind of hard to visualize what he is trying to do.

or you could select the vertices you want flatten, then put the cursor some long distance away & the spere it. then move the vertices closer to the sphere

select a few faces and change transform orientation from global to normal, then press s for scaling and twice z for z-direction along normal

And after that’s done, you can just type in 0 (zero) and <Enter>, instead of using the mouse to scale down to 0.