Yes, you can create a Purchase order based on the sales you did in that same period. You'll have two options on how to perform this. You can copy the PO with the same period in the Expenses page and use the Reorder feature in QuickBooks Online. Please make sure to review or enter the same information before saving.
From the Expenses page, here's how:
Click the Expenses menu on the left panel.
Choose the Expenses section and locate the PO.
Click the drop-down arrow under the Action column. Then, choose Copy.
You'll be routed on the Purchase Order page and review all the details entered.
Fromthe Products and Services page to use the Reorder feature, follow these steps:
Go to the Sales menu at the left panel. Then, choose Products and Services section.
Select Low Stock or Out of stock. If you need to reorder both low stock and out of stock products from the same vendor, don’t use any of the filters at the top.
Click the product you want to reorder. Then, go to the Batch actions button and choose Reorder. This creates a purchase order for a single vendor.
Complete all the details of the purchase order, or add other items you need to reorder from the vendor.
You can definitely run reports to see your sales to know what your customers wants.
You can have the Sales by Product/Service Summary and Sales by Product/Service Detail report to see thetotal sales and sale transactions by item/product or service.
I also suggest generating either Inventory Valuation Summary, Inventory Valuation Detail, or Physical Inventory Worksheet to check what’s on hand and send a purchase order to your vendors, so you always have what your customers want.