You can design Avery Print & Apply Index Maker 12-tab dividers using the 11404 template in Avery Design & Print Online.
You can also use a template built into Microsoft Word or download an Avery 11404 template for Word, Photoshop, Illustrator, InDesign or Pages.
Here's some information on recommended printer settings.
If you want more information about a specific Avery divider, search for the product number on avery.com.