When someone clicks your ad, like on the blue headline or phone number of a text ad, Google Ads counts that as a click.

• A click is counted even if the person doesn't reach your website, maybe because it's temporarily unavailable. As a result, you might see a difference between the number of clicks on your ad and the number of visits to your website. For YouTube on TV screens, clicks reported are for actions taken on the TV call-to-action button (CTA), not for actions taken on follow-up notifications.
• Clicks can help you understand how well your ad is appealing to people who see it. Relevant, highly-targeted ads are more likely to receive clicks.