You can find the attachment that came with the purchase invoice directly from the purchase invoice, by opening the invoice. You can find purchase invoices in the main menu. Keep in mind that purchase invoices are filtered by default for Unhandled, but you can also filter them by Paid or Hidden invoices.
To find an attachment, first open a purchase invoice:
After that you can check whether that invoice has attachments or not and you can download them from there directly:
Note. This feature is currently only available to companies registered in Finland.