Web Accessibility refers to apps, websites, and digital tools designed to be accessible by all users, including those with disabilities. The web is a source of public information, education, employment, government, commerce, health, entertainment, and many others, and every person, regardless of ability, has the right to access it. Imagine missing out on thousands of new customers because your competitor has an easier-to-use, WCAG-compliant website. This systematic literature review aims to analyze the empirical methods of evaluating accessibility to educational websites, disabilities, and errors. Some of the papers we will review here use automated tools, real users, or experts to evaluate web accessibility. After analyzing the results, we will determine if the websites comply or not with the Web Accessibility Content Guidelines (WCAG). Also, what are the differences between automated tools, real users, and experts in evaluating websites.