Outlook lets you add an expiration date to email you send or receive. Once the expiration date has passed the email will be displayed with different formatting, and you can use Outlook’s built-in tools to manage expired email automatically.
Expiration dates only apply to emails, not calendar events or tasks because those items have their own dates you can use for managing them
How to Set an Expiration Date on an Email
To add an expiration date to an email you’re sending, you need to open the Properties window for the email. Open the email and then click Message > Tags.
This will open the Properties window for the email, which you can also access by clicking Options > More Options, or File > Properties. Switch on the “Expires after” checkbox and then choose a date and time.
Click Close to return to your email. There won’t be any visible signs that an expiration date has been added, and you can send the email as normal.
To add an expiration date to an email you’ve received, open the email and click Message > Tags (or File > Properties).