You can create purchase orders directly from your sales orders if required. You can allocate stock automatically, when it is received, to the Sales Order line ready for despatch.
To create purchase orders from sales orders, you must have chosen the From Supplier via Stock option for stock item fulfilment for each stock item.
You have two options for creating the purchase orders:
Create a separate purchase order per supplier for each sales order.
Select the Save and Generate PO option on your sales order.
Create one purchase order per supplier for all sales orders.
Use the Generate Purchase Orders option in your Purchase Order Processing module.
In both cases you can see details of the linked sales order on the relevant purchase order.
Note: Save and Generate PO uses the Generate Purchase Orders option.
What do you want to do?
Create a back-to-back sales order
Create purchase orders from back-to-back sales orders
Other tasks
How do I complete a back to back sales order when only part of the quantity has been delivered?
Reference