If someone did an order, the invoice PDF is send to that customer. But where can I see that invoice on the orders admin page? I mean I see “PDF Invoice” button with a green checkmark at “Make PDF” but is that the generated Invoice PDF?
Yes, when you see the green checkmark next to the button label or in the document icon (in the order list), that means that the PDF document was generated and a number was reserved for it.
For previewing a document, without generating it yet, you can go to WooCommerce > PDF Invoices.
If the document button or icon has a green checkmark, it will open the existing invoice; it will not create a new document. In summary, by default, you should obtain the same document that you send to your customers by email attachment.
Just note that our free plugin generates the documents on the fly, that is, the PDF documents are not stored in your server as such, but they are created at the moment of the request, using the document data saved in the order for existing invoices or creating them first for new invoices, and then the document is rendered. I mention this because if you apply some changes to the layout, it will affect the design of old invoices as well, although the document data as such should not be touched, e.g. the invoice number, invoice date, etc., should remain the same.
In the case that you’re looking to save the PDF documents in your server when they are generated, and keep them immutable, even if you perform layout/design changes in the future, then you would need to get the Professional extension to enable the “Keep PDF on server” option included in this plugin: