Google Adwords allows advertisers to create paid search advertising campaigns on Google and its partner sites. Advertisers pay for these ads on a cost-per-click basis, meaning they only pay when someone clicks on their ad. Effective campaigns require identifying relevant keywords, testing different ad text and landing pages, and using reporting tools to measure results and optimize campaigns over time. Campaign structure and match types can help control where ads appear based on searches. The goal is to increase clicks and conversions while maintaining a reasonable cost per click. Targeting options allow focusing ads by location, language, country or custom regions.