Credible sources are essential in informative essays because they provide a foundation of trustworthiness and reliability for the information presented. Using credible sources helps establish the author's authority and expertise on the topic, enhancing the essay's overall credibility. Readers are more likely to accept and rely on the information if it comes from reputable sources, making the essay more persuasive and informative. Additionally, citing credible sources allows readers to verify the information independently and fosters transparency and accountability in the research and writing process. Overall, credible sources are the cornerstone of well-substantiated, fact-based, and reliable informative essays.