Forum Discussion
How to apply sensitivity labels to external emails received in my Outlook?
I have created a sensitivity label and an auto-labeling policy that applies the label when an email contains sensitive information. When an internal user sends the email, the label is applied correct...
If got your discription right: What Jalixio​ writes.
If it comes to something like 'all emails from mailto:email address removed for privacy reasons' you can use mail flow rules as an trigger.