Hi there justin-harbers14,
Thanks for reaching out about emailing invoices. QuickBooks Online is a great tool able to assist in creating and sending transactions for your customers. I can provide some information about errors when sending forms by email.
If a customer isn't able to receive invoices or other forms you're sending them from QuickBooks Online, you can try the steps in this article. There are a few different methods to resolve errors for a customer unable to receive the emails sent.
If you have any other questions, feel free to reach out here.
