In newer version:
Click the Company Gear (upper-right corner)
Select Sales
Click “Messages” (it’s inside; not visible from outside)
Check box that reads “Email me a copy”
Save
How to email me a copy of Invoice in new QuickBooks Online?
In newer version:
Click the Company Gear (upper-right corner)
Select Sales
Click “Messages” (it’s inside; not visible from outside)
Check box that reads “Email me a copy”
Save