Invoices are automatically emailed to the billing contact on file in your Libris account on the subscription or add-on renewal date. After this invoice is sent by email, the invoice is also visible in your Libris account under Admin > Account Settings > Statements for the Admin/Editors to view, save, and print.
From the Statements page, click the invoice number in the list to view the complete invoice details.
Click "Printable Version" and a similar view will open in a new tab.
Right-click on any of the whitespace in the window to open the dropdown dialogue box where you can select to Print this page (or click File > Print in your web browser menu bar).
The next view might default to your office printer. If it does, click "Change" to switch to "Save as PDF"
When you "Save", be mindful of the location you are saving the file to (Desktop, Downloads folder, Documents folder, etc.)
Now that you have the PDF version of your invoice saved to a location on your computer, you can open the document in an editing application (like the Preview application on a Mac) and add any text (like a PO code) required and save and print. Below is an example of how to edit the invoice in Preview: