Adobe's InDesign software program allows users to make customised graphic and textual layouts for both print and Web use. The program includes the ability to create customised stroke patterns and lines with edges and endpoint artwork, including arrowheads. Although the arrowheads and other stroke endpoints are sized automatically in proportion to the weight of the stroke lines, you can create a larger arrowhead by separating it from the stroke using the native InDesign tools and rejoining them using the "Group" command.
Use the "Selection Tool" from the tools panel on the left of the InDesign application window to click on and select the stroke containing the arrowhead you would like to enlarge.
Choose the "Scissors Tool" from the tools panel. Click on the portion of the stroke that appears just in front of the arrowhead. This will split the arrowhead off from the stroke and create a second stroke arrowhead in front of it. Choose the "Selection Tool" once again, and then click on the arrowhead that was split off from the stroke.
Open the "Stroke" palette on the right side of the InDesign application menu. Increase the "Weight" field until the arrowhead is displayed at your desired size.
Choose the "Selection Tool" once more. Click and drag the split, resized arrowhead in line with the original stroke. Click on the stroke while holding the "Shift" key to have both the arrowhead and stroke line selected simultaneously. Select "Object" followed by "Group" from the control menu atop the screen to create a single object out of the stroke and enlarged arrowhead.
Save your enlarged arrowhead by selecting "File" followed by "Save As" from the control menu.