You don´t see the tile 'Create Purchase Order' in the fiori Launchapd.
On cloud , from 1705 Release.
In previous releases you can see two different tiles for each App:
Create Purchase Order.
Manage Purchase Order.
The same OData Service (MM_PUR_PO_MAINTAIN) is used for both apps. From a technical point of view both apps are just one. The functionality of "Create Purchase Order" app, has been included in the Manage Purchase order App.
You can use create new Purchase orders just using the '+' that you can see in the list of the purchase orders.
Create purchase order, manage pruchase order , KBA , MM-FIO-PUR-PO , Fiori UI for Purchase Orders , Problem