It's not uncommon to have a situation where you'd like an email to be sent out at a later date and time from the moment you create it. Perhaps you'll be on vacation next week, and you want to remind someone that their report is due on Wednesday with a reminder email sent to them on Tuesday. You can do that in Outlook!
To delay the sending of an email, create an email like you normally would:
Instead of sending it like normal, click on Options > Delay Delivery
The Dialog Box gives you the option, among other things, to not deliver the email before a set date and time:
Once you do that, your email will sit in your Outlook outbox until your delivery date shows up. Once it does, your email will be sent, just as if you were sitting there in front of your computer (while instead you're sitting on the beach enjoying a book, the sun, and a refreshing beverage):