Good day, @tommy5.
I can share some insights on how the email feature works in QuickBooks Online.
Currently, the ability to write other type of emails and send it to your customer is not yet available. You need not to worry, you can email 6 types of sales transactions to your customers from QuickBooks Online.
Also, you can send reports directly from QuickBooks Online to multiple customers at the same time. You can either manually enter multiple email addresses separated by a comma and space or use the CC or Bcc fields.
Always get back to us here in the Community if you have other questions about sending emails from QuickBooks Online. I'm always here to help.