I have some emails that come through the main email box that is connected to Zendesk. However, I want to use that main business email address outside of Zendesk. Can I send an email in my inbox and prevent the reply from creating a ticket?
If you connected your external email address to Zendesk with a forwarding rule, any email reply will create a ticket in your account. All incoming emails to the email address you forward into Zendesk create a ticket.
If you want to notify a user and prevent them from seeing the back and forward on a ticket, consider using side conversations in tickets. For more information, see this article: How do I forward tickets to an external user?