On iPads, it is not possible to reach to the detail-level of an assigned workitem. On desktops, you need to perform a "double-click" - on iPads you would need to do an double-touch, which seems like an uncommon gesture to select something (to me) - and I didn't succeed in getting to the detail-level of a assigned workitem.

On desktops, in Chromes emulation of iPad, I can sometimes reach the detail-page by double-clicking fast - but on this page, there is no "Approve and publish" button, as shown in the screenshot ipad-no-approve-and-publish.png. So, it is not possible to perform a publication via iPad.

The solution could be to show the "Approve and Publish" action on the action-menu on the bottom of the page, see screenshot ipad-approve-and-publish.png