Thanks for posting in the Community, @gracebaptistchur.
It seems that the purchase order (PO) numbers you're referring are issued by your customers. If so, let's first add a custom field for the PO numbers to appear on your invoices. Let me guide you how.
- Go to the Settings (Gear) icon at the upper right.
- Select Account and Settings under Your Company.
- Go to Sales from the left menu,
- Click Sales form content.
- Under Custom fields, enter PO Number in the Name field.
- Mark the Internal and Public boxes.
- Choose Save.
- Hit Done.
The screenshot below shows you the last six steps.
![AddPONumberCustomField.PNG AddPONumberCustomField.PNG](https://quickbooks.intuit.com/learn-support/image/serverpage/image-id/36818i458A89CBD1A1429F/image-size/large?v=v2&px=999)
Once done, create an invoice and manually put the PO Number in the custom field. Then, click Save as seen in the screenshot below. Repeat the process for other invoices.
![PutPONumberInTheInvoicePage.PNG PutPONumberInTheInvoicePage.PNG](https://quickbooks.intuit.com/learn-support/image/serverpage/image-id/36819i54A0CFCE63474050/image-size/large?v=v2&px=999)
After that, you can search for your invoices by using the PO numbers. I'll guide you how.
- Go to the Search (magnifying glass) icon at the upper right.
- Click Advanced search.
- Choose Invoices from the transaction type drop-down.
- Select Custom Field:Field 1.
- Manually enter the PO number in the Enter Custom Field box.
- Hit Search.
See the screenshots below to show you the steps.
![SearchPONumber1.PNG SearchPONumber1.PNG](https://quickbooks.intuit.com/learn-support/image/serverpage/image-id/36820iBA84743C50818847/image-size/large?v=v2&px=999)
![SearchPONumber2.PNG SearchPONumber2.PNG](https://quickbooks.intuit.com/learn-support/image/serverpage/image-id/36821i6946F1DABC8A493C/image-size/large?v=v2&px=999)
You can always run and customize the Transaction Detail By Account report in the program. This lets you view all your invoices that are due on a specific period. Just go to Reports from the left menu and enter the report name in the Search box. Then, click Customize, set the Transaction Type to Invoice, and A/R Paid to Unpaid. For more details, check out this article: Generate An Invoice By Due Date Report.
I'm here anytime you have other concerns. Have a great day, @gracebaptistchur.