Quality Score is a metric used by search engines like Google to evaluate the relevance and quality of your PPC ads, keywords, and landing pages. It considers factors such as click-through rate, ad relevance, and the quality of the landing page. A higher Quality Score can result in lower costs per click and better ad positions. To improve Quality Score, focus on creating relevant ad copy, choosing targeted keywords, and optimizing landing pages for a seamless user experience. A higher Quality Score not only improves ad performance but also helps in achieving a better return on investment (ROI).