Hi Lisa! You can't add an attachment to a Wave invoice, but you can export your invoice as a PDF and then attach it along with anything else you need to send to your customer to an email.
If I do export the invoice as a PDF, is it clickable? Meaning, can the client click on it to pay online? TIA!
@Mariedyth The invoice itself wouldn't be clickable since it's a PDF, however, you can still include the payment link associated with the invoice (you can just copy and paste it in the email that you are sending to the client) -- you can find this on the invoice itself if you click on 'More Actions' and select the 'get share link' -- see screenshot.