Gmail now lets you add emails as attachments

How it works: Highlight messages that you want to attach to the new mail. You can now attach emails to other emails in Gmail without downloading them first.

Hold the left click on the mouse until you see the blinking cursor. Users can either use the attach button when drafting a new email or can select multiple emails, and find the option of "Forward as attachment" in the three-dot menu.

Drag highlighted messages to the draft window. There is no need to create a brand new thread for replying to an email, as well. Just pop out the draft window when replying to someone, then drag and drop emails to it like a user would do while creating a new draft entirely.

Draft window will change to show where emails can be dropped. The feature will be rolling out to all G suite editions gradually within the next month.

Emails will show as attachments on the draft window.

Another way to insert emails in a new thread is to select the emails and then from the overflow (three-dot) menu select “Forward as attachment”.

To reply to an existing thread, you can pop-out the compose window and then drag and drop emails to it.