You will need to create the emails manually and link to the invoices using the internal invoice id. You can find the pattern by emailing yourself an invoice out of the admin manually.
Unfortunately the api does not have an email invoice endpoint.
Thank you for your insight. It is unfortunate that isn’t part of the API.
I saw this and was hopeful that it would allow me to send emails through an API call:
I am going to try the following in Make: Generate the invoices, then get a list of those invoices, store that info in a Google Sheet, then create and email the members with a link to their invoice using Gmail.