Ad extensions add extra information to your ad, making it larger and more useful without extra cost — and often improving click-through rate. This lesson covers the most useful extension types: Sitelinks (links to specific pages like “Contact Us” or “Pricing”), Callouts (short highlights like “Free Shipping” or “24/7 Support”), and Call extensions (a clickable phone number, useful for service businesses). Using multiple relevant extensions consistently improves both ad visibility and Quality Score.