Starting in macOS Ventura, you can unsend an email in Mail on your Mac
After you click Send,
a button that says Undo Send, will appear in the bottom-left corner.
By default, this button will be available for 10 seconds.
If you'd like more time, you can change this in your Mail settings
and have the button stay active for up to 30 seconds.
Click Undo Send if you want to stop the email
and your original email will reappear
for you to edit or make changes.
Then, click Send once it's ready.