You can tag an email as private, to let recipients know that they should treat the information it contains as private. However, nothing prevents them from forwarding or printing that message. To restrict what recipients can do with a message you send, you have to use Information Rights Management (IRM).
Your system administrator has to install IRM before you can apply restrictions to an email. If you don’t see the Permission button (on the Options tab), IRM probably isn’t set up.
Important: You can view IRM-protected mail using Outlook 2013 RT, but you can’t send. Want to see what version of Office you're using?
In your email, on the Options tab, click Permission.
Outlook sets the Do Not Forward permission (which also prevents printing) and adds the following message to the top of your email:
Important: IRM can’t prevent content from being erased, stolen, corrupted, or captured and transmitted by malicious programs or computer viruses. It also can’t stop people from writing the content out by hand, retyping it, or taking a digital photograph or screen capture of the message.
Tip: Outlook has a bunch of permission settings you can choose from. To see the list, click the arrow below the Permission button.
Tag a message as private (this doesn’t prevent sharing or printing)
If you just want to let people know that you’d like them to treat your email as private, you can tag it as such. This doesn’t stop them from forwarding or printing your message. Instead, it includes “Please treat this as Private” at the top of your email:
In your email, click Message, and then click the arrow in the bottom right of the Tags group.
In the Properties box, click the Sensitivity arrow, and then click Private.
You won’t notice any changes to your email after you tag the message as Private. But the person who receives your email will see Please treat this as Private at the top.
You may have noticed that there were other Sensitivity options to choose from, including Personal and Confidential.
The person who reads your email will see a slightly different message, depending on which option you pick.
Personal shows Please treat this as Personal at the top of the email.
Private shows Please treat this as Private at the top of the email.
Confidential show Please treat this as Confidential at the top of the email.