In the invoice email we sent you, you can find a link to your personal store portal, which directs you to your invoice page.
On your invoice page you will find two PDF files:
1. Your invoice
2. Image scans of your customers original receipts and their tax-free forms
It is possible that the PDF files still need to be generated. In that case you will see a lime green 'create images PDF' button at the bottom of your invoice page. If you click this button, the PDF's will be generated for you.