Hey there, Sheanmei.
Thanks for turning to the Community for support. I'd be glad to provide some info about the feature that allows you to combine emails in your Desktop account.
The feature that enables users to combine multiple emails in one message is referring specifically to invoices. By using this option, you'll be able to easily send several invoices to the same customer at one time, rather than having to send each invoice individually. The following article provides an overview of new and improved features for the 2020 edition: What’s new in QuickBooks Desktop 2020
Additionally, I invite you to check out the QuickBooks Blog for even more info on up and coming product releases and updates.
Please know I'm only a comment or post away if you have any other questions. Take care!
