Open your design software on your computer. Commonly used software includes Adobe Photoshop and GIMP. Make a new document by clicking on "File" from the menu bar and selecting "New Document." Make the size a standard letter, or 8 1/2 inches by 11 inches.
Mark out four lines using the "Line" tool from the tool menu defining the design area and fold locations. The lines on the side will be about 1 3/4 inches from either side. The top line should be at about 1 5/8 inches from the top edge, and the bottom at about 4 3/4 inches from the bottom edge.
Draw out and design the art for your CD envelope. Have the title in bold letters. Use a lot of exciting images and make it colorful. Save your file when you're done.
Click on "File" from the menu bar and select "Print." This will bring up the print window. Everything should be set to default letter size. If not, change the page size to letter, or 8 1/2 inches by 11 inches. Click the "OK" or "Print" button when ready to print.
Turn the printout over so the art is facing down on your workspace. On the lines you made earlier, fold the lines on the sides first. Apply glue to the bottom edge and glue it down so now the bottom fold is joined to the two sides you folded. Slip the CD into the envelope and fold the top section down, closing the CD envelope.