Job items are not added to invoice or quote
Check that the template setting to Copy job inventory for new document is checked.
Purchase Order number not showing on PDF
If the customer Purchase order number is not showing on the PDF check the template for the specific PO that it's using
There are three ways to show the customer PO number
{invoice-purchase-order-number} - This is the Purchase Order Number field as on the Invoice - use this if you have one custom purchase order number for an invoice
Under the job details - Use this if you have several jobs with different Purchase Order numbers on one Invoice and you want to show the Purchase order number field for each job in the job details
{purchase-order-number} - Job purchase order number field on the first job