C4 Envelope, C5 Envelope, C6 Envelope, DL Envelope, Custom. Units Determine the unit of measurement for all measurable files in the drawing. This field determines what unit the rulers display, for example, as well as what the dimensions of the page will be measured in. Options are Inches, Centimeters, Picas or Points. Scale Select at what scale you want to display your drawing.
Dimensions Specify the exact dimensions of the entire page.
Margins Specify the dimensions of the margins. Number of Pages Specify the number of pages in the entire diagram. The gray numbers in the boxes specify the page sequence for printing. The Page Layout dialog has an Apply button. You can make changes to your page layout and keep the dialog on the screen.