When you send an email, Outlook sends the original email to the recipient and stores a copy of that email in the “Sent” folder. This default behavior makes sense, of course, and will likely never change, but that doesn’t mean you can’t change it if you don’t like it.
Outlook gives you the option to disable the feature so that it doesn't save copies of your sent emails in the Sent folder. If you usually delete everything in the Sent folder, then you're covered and don't need to do the process we're presenting below.
To automatically move emails to a folder outside of Sent, you stop Outlook from saving a copy in your Sent and create a rule that sends a copy of all your sent emails to a folder of choice .
The process we are interested in is set as the default for all emails, but you can also do it for a single email. In the Outlook application, open the “Options” tab and click on the “Save Sent Item To” option, which will give you the option to specify a specific folder or not save the sent email at all.
Of course, we can't think of many circumstances where you would be comfortable doing this . However, if you still want to do it for all emails, here's how.
How to stop Outlook from saving your sent emails
To prevent Microsoft Outlook from saving a copy of your sent emails, open File > Options.
On the “Mail” tab, scroll down to the “Save Messages” section and uncheck “Save copies of messages in the Sent Items folder.”
Now click “OK” at the bottom right of the “Options” window.
If you just want Outlook to stop saving your sent emails, that's all you need to do. You're good to go !
Information source: howtogeek.com
