What is the easiest way to add the contact of someone who sent you an email?
Create a rule to apply conditional formatting to all messages where you are in the cc line.
Double-click the sender's email address in the message and select Add to Outlook Contacts (Windows) or Open Outlook contacts (Mac).
Right-click the sender's name in the message and select Add to Outlook Contacts (Windows) or Open Outlook contacts (Mac).
Copy and paste their email address into a new contact form.