HI @Paul Russo,
Welcome to Microsoft Q&A Forum, thank you for posting your query here!
You must have an owner or a contributor role on the billing profile or its billing account to update its email invoice preference. Once you have opted-in, all users with an owner, contributor, readers, and invoice manager roles on a billing profile get its invoice in email.
Please refer to the below article which will help you to the send by email and invoice email preference invoice
Refer below:
Feel free to reach out if you have any further questions or need additional information—I’m happy to assist!
Please provide your valuable comments
Please do not forget to "Accept the answer” and “upvote it” wherever the information provided helps you, this can be beneficial to other community members.it would be greatly appreciated and helpful to others.