IPN is used for post-transaction processing. The “invoice ID” that you’re seeing would be populated if you included that in your payment request.
For example, if you were using WooCommerce and our PayPal for WooCommerce plugin, then the invoice ID would be the WooCommerce order ID.
Or are you referring to a receipt as opposed to an invoice? A receipt would be proof of purchase, where-as an invoice would be something that still needs to be paid.
If you’re wanting to generate a custom email receipt / notification then yes, you could use this plugin to get that done easily. You would just need to build a hook function that generates an HTML and sends it off using wp_mail() or whatever you’re comfortable with.