Choose the purchase order that you want to archive and click on it'sSmall and choose Archive. archive
At Confirmation pop-up window click on OK.archive
Also to archive a purchase order, you can click on it, click on Actions then choose Archive.archive.png
To restore/activate an archive purchase order, first of all you have to go to archived orders by clicking on the Big and choose Archived Purchase Orders.
From here you will have to click on order's Small and choose Restore.archivearchive
At Confirmation click OK.archive
Also to reactivate an archived order, you can click on it, then click on Restore.restore