Under the editable mesh options, there are two fields: extrude and bevel\chamfer. Select the faces you want to extrude and raise the value in the extrude field to do as such. By "peak", i assume you mean to merge the extruded face into one point. To do that, either use the bevel field or scale down the extruded face. Then weld the vertices into one point.
I only hope you can understand this technical jargon.....
good luck