Page Size and Orientation
Change the page size by typing in new values for width and height. Page size represents the final size you want after bleeds or trimming other marks outside the page. In the Preset drop down menu you can find such common sizes as letter, legal, tabloid, etc. Typing in exact values for Height and Width gives you more control over the size and orientation of your page.
Resolution
Resolution is a number of pixels on a printed area of an image. The higher the resolution, the more pixels there are on the page, the better is the quality of the image. However, high resolution increases the size of the file. The standard recommended resolution for printed images is 150-300, for Web images it is 72.
Color Mode
Choose a color mode that will best fit your project. For example, when making a graphic for a web site, choose RGB. When making an image for print, choose CMYK.
Background Contents
Choose the background: white, color, or transparent. When you have entered all of your document settings, click OK.