Field help (PNHFCY) 

The site code is initialized by default to the storage site code associated with the connected user. Click the selection window from the Actions icon to select a site from the user’s list of authorized sites.
There is no restriction on the sites, namely to authorize the return of the products that are not managed in stock at sites that do not have a warehouse role. This can be the case for instance for miscellaneous supplies.
At this stage, the Receipts selection panel is dynamically initialized making it possible to choose the receipts or receipt lines to be processed. You can add filters in the return header or in the Picking criteria window to restrict the list of suggested receipts.