Open Outlook and compose a new email
Fill in the recipient, subject, and message
Go to the Options tab
Select Delay Delivery or More Options
Check Do not deliver before
Choose the date and time you want the email sent
Click Close
Click Send
Keep Outlook open until the scheduled send time if required by your version
For Outlook on the web, open the message menu and choose Schedule send
Select a suggested time or pick a custom time
Confirm the scheduled send time