The Choose Via Sizes dialog allows you to select a via from the list of vias used on the current PCB board. The dialog displays the diameter and hole size of the vias.
The dialog is accessed in the PCB editor by pressing Shift+V while interactively routing (Route » Interactive Routing).
Select a Via in the left-hand pane of the dialog to view the sizes for that Via. When you select a Via, the right side of the dialog displays information for the selected Via.
Simple(Via hole size and diameter are the same through all layers),
Top-Middle-Bottom(different Hole Size and Diameters can be set at Top Layer, Middle Layer and Bottom Layer), or
Full Stack(different Hole Size and Diameters can be edited at each layer, including all signal layers and planes).