To get an email header from Yahoo! simply open the email within your web browser, click the ...More drop down arrow and choose "View Full Header".
Once the data window opens (example not shown for security reasons), select Ctrl+A then Ctrl+C on a PC. On a Mac, select Cmd+A then Cmd+C to copy all data within the window.
Once all data is copied, head over to our Email Header Analyzer Tool and paste (Ctrl+v for PC or Cmd+v for Mac) that data into the tool window. Hit Analyze to get your results.