The Archive function removes the form from the 'All' view and any other view the excludes archived forms. You can easily unarchive forms by selecting the 'Archived' built-in view, view the form and unarchive (screenshots further down below).
Use: to keep your 'All' view with just forms that are currently being worked on. In certain cases users archive forms (orders) to exclude them from reconcile.
Click next to All to open the dropdown and select Archived.
After you View the form click Unarchive.