1. Log in to the Microsoft 365 Admin center at https://portal.office.com
2. Open the Exchange Admin center.
a. Admin Centers > Exchange
3. Select Mail Flow
4. Create a new rule.
5. Enter a name for the rule.
6. For Apply this rule if… Select “The sender is located…”, then choose “Outside the organization”
7. Add a condition.
8. For Do the following…, select “Apply a disclaimer to the message…” , “prepend a disclaimer”.
a. Click, Enter Text
b. Enter the message you would like to see. Here is what we use:
c. <div style="background-color:#FFEB9C; width:100%; border-style: solid; border-color:#9C6500; border-width:1pt; padding:2pt; font-size:10pt; line-height:12pt; font-family:'Calibri'; color:Black; text-align: left;"><span style="color:#9C6500; font-weight:bold;">CAUTION:</span> This email originated from outside of the organization. Do not click links or open attachments unless you recognize the sender and know the content is safe.</div><br>
9. Specify a fall back option.
b. Select Wrap
10. Set the priority based on any other rules you may have. We set ours to 0, so it will be the first rule triggered and applied to all messages.
11. Click Save!