Thanks for providing me with the details, @aquaclear.

Let me share some insights about setting up your email in your QuickBooks Desktop (QBDT) software. There isn't a specific email provider that works best with QBDT. QuickBooks lets you add an email address base on your preference.

Also, the QuickBooks Email is only available when the system detects you have an active subscription for any company file to: 

• QuickBooks Connect.
• Intuit Data Protect
• QuickBooks Time and Billing Manager.

For more details in connecting your email to your QBDT software, you can always check this article for reference: Connect your email to QuickBooks Desktop.

Lastly, you might want to check this handy article that can guide you in making your business to stand out of the rest: Use and customize form templates.

Please know you're always welcome to post here anytime you need help. I'll be around to lend a hand. Have a great day!