Gmail Headers
Open mail.google.com
Open the email you wish to view the headers of.
On the top right of the email next to reply, click the three dots (more) → Show original.
Outlook Web
Open outlook.live.com
Open the email you wish to view the headers of.
On the top right of the email, click the three dots → View → View message source.
Outlook App
Open Outlook.
Open the email you wish to view the headers of.
Click File → Properties.
Headers will display in the "Internet headers" box.
Apple Mail
Open Apple Mail.
Open the email you wish to view the headers of.
Click View → Message → All Headers.
Headers will display in the window below your inbox.
Yahoo Mail
Click on an email to open it.
Click the More icon (...).
Select View Raw Message.
Proton Mail
Web App
Log in to your account at mail.proton.me and open an email.
Go to More (3-dot icon) →View headers.
Android / iOS
Log in to the Proton Mail app and open an email.
Tap the 3-dot menu icon at the bottom right of the screen →View headers.
Zoho Mail
Open the email whose headers you would like to view.
Click the More Actions drop-down on the right corner of the email.
Choose the Show Original option.
Don't see your email client listed? Odds are that a quick search of your mail client's documentation will show you how to view email headers. If you're still having issues, give us a shout and we'll help you find them!