The WooCommerce “Customer Invoice” email is a manual email, you can’t change that, unfortunately. Instead though, you can attach the PDF to any of the other emails, for example the Processing or the Completed email.
Hope that helps!
Thanks for the response Ewout.
I tried what you said but I am still not getting a email when I test order with the email I provided.
Is there a CSS code I can put in to force it to send to customer emails?
Hi! There could be several reasons for the email not arriving, but they are probably unrelated to the PDF invoice plugin. You could instal WP Mail Logging which well let you see which emails WordPress tried to send (and also show you the accompanying attachments). If the email is not there, make sure it is enabled in the WooCommerce settings (WooCommerce > Settings > Emails), and that you have actually set the order to the correct status. You can manually resend the email with the order actions in the top right of the order edit page. Note that only the ‘new order’ email is sent to the admin, all other emails are sent to the customer.
If the email is being logged by WP Mail Logging but not arriving in your inbox check your spam folder and check this page for tips on improving mail delivery: