How to Schedule Sending an Email in Gmail
Gmail now lets you write an email and schedule a sending time. Schedule an email for later, and it will go out at the specific date and time you choose. It’s particularly convenient for replying to emails outside business hours.
Google added this feature in April 2019. Scheduling emails previously required a third-party extension like Boomerang. It’s now built into both Gmail’s website and the Gmail app. You can have up to 100 scheduled emails at a time.