If you wish to track voids with a specific list of reasons, you can require employees to enter a void reason and you can create a custom list of reasons for them to choose from.

Navigate to Configuration > Security.  About half way down the POS functions section you will see the "Require Reason on Voids".  Check the box for each workgroup you wish.

Once you've created your list of reasons, this is what will happen when you try to void in the POS.