Here is a more detailed article about advanced voucher management.
First, click on Vouchers at the top right.
You will see the screen below.
Below this screen is the Manage Vouchers area.
By default this section will show you your current, valid vouchers. In the Voucher column are all the details of the voucher, including category/product restrictions.
Use the Filter by Status dropdown to display expired, cancelled, and redeemed vouchers. Select an option from the dropdown, then press Filter & Sort.
Below the vouchers are more options.
First, select vouchers above. Then choose one of the options. If a voucher is used in-store (eg, is printed out then taken to your physical store), select Redeem In-Store.
You can also disable/enable the ability to redeem vouchers online.
Select vouchers and press Cancel to null a voucher.
Back above the voucher list, you can filter the list by In-Store Only, Redeemed, or Cancelled to view the vouchers with new statuses.