For those using Outlook client, you already know that you can delay sending the email by accessing the Options\Delay Delivery button.
Well, good news, this is now also possible for those using Outlook Web Access (aka OWA, aka Outlook on the Web).
When writing a new email, you can choose to delay the delivery but using the menu on the left side of the bottom SEND button.
You need first to define your recipient(s) and write your email
Then you can define a date and time when the email will be indeed sent
NOTE the current date is shown with a circle while a future date is showing with a square
When hitting the Send button at this stage, your email will be queued to be send at the date/time you define
NOTE during this period, your email is being saved in the Draft folder
When you access the Draft folder and look at the delayed email, you will see a note telling you your email is scheduled for a delayed delivery and on the far right side you can click on Cancel Send to cancel the delay
You can not read your email in the delayed status; you will need to cancel sending the email to be able to view the email and may be edit it too.