Adobe Illustrator offers users the ability to create professional quality designs that you can use for any type of application, from Web pages to printed media. Illustrator has tools that allow for almost limitless creativity. However, it also comes with hundreds of built-in shapes, effects and image enhancers to make simple tasks even easier. Among these is the ability to add custom arrowheads that you can design with just a few clicks.
Open a new document in Adobe Illustrator.
Create an object on the blank canvas. For this example choose the line tool and draw a straight line with any dimensions and characteristics.
Select the object directly or click on the target layer in the layers panel.
Click on "Effect" from the menu options, choose "Stylize" and then select "Add Arrowheads."
Mark the check box next to "Preview" and use the arrows to scroll through the available arrowhead designs for both the "Start" and "End" positions.
Enter the desired scale for the arrowhead. The scale is determined relative to the stroke chosen for the object that you first created.
Click "OK" to create the arrowhead and complete the process.