You can void checks both before and after they have been printed.
Before the print run, you would void blank checks that are accidentally damaged, or stolen or rendered unusable for any other reason. To void checks such as these, proceed as follows:
Checks that are voided after the print run, for example, are those that are not required due to cash payment being chosen instead of by check. To void printed checks, proceed as follows:
You can find further information on how to proceed when checks are voided by mistake under Deleting or Resetting Check Information.