If you regularly forward email, including using mailing lists or inbound gateways, add ARC headers to outgoing email. Gmail will begin using a DMARC quarantine enforcement policy, and impersonating Gmail From: headers might impact your email delivery. Your email header is not the place to experiment with new, off-the-wall ideas.Don’t impersonate Gmail From: headers. The header should be strongly branded, including your logo and key colors. Size is important-strive for your email headers to be less than 70px high if they don't have a menu, or less than 200px if they do.