Here are some best practices for making it clear that your email is an advertisement:
Subject Line: Include language that indicates the nature of the email. Phrases like "Special Offer" or "Exclusive Deal" can make it clear. Header Information: Ensure your sender information is accurate and recognizable. Avoid misleading or deceptive subject lines. Footer Information: Clearly state that the email is an advertisement somewhere in the email, often in the footer. Include your physical mailing address and an easy way to unsubscribe.