Select an Edit Poly or editable poly object. > Modify panel > Vertex/Edge/Border sub-object level > Edit Edges rollout > Chamfer
Settings button
Select an Edit Poly or editable poly object. > Vertex/Edge/Border sub-object level > Quad menu > tools 2 quadrant > Chamfer
Settings button
Chamfering creates new faces around the chamfered entity, along with connecting edges. Or, with the Open option, you can create an open (empty) area instead. This dialog is the same for chamfering vertices, edges, and borders of poly objects. You can use it to set the chamfer amount numerically, and to toggle the Open option.