Up-to-date standards are offered for checking compliance, and it provides a cost-effective way to scan a site for compliance. There's services out there where it'd cost more than $150 (the current cost of a 1 site 1 year license) for the size of the sites I'm working with. I'm very happy to see this offering in the first place, and it's even nicer to see how thorough it looks to be. Of course, it's not perfect so I'd love to see more of the WP.org listing fleshed out (the developer author/contributor mention is missing, etc.), I'd love to see the free version on GitHub (or similar for community development assistance [I have a few things I'd help with] which is very nice to see in a WP.org listing to show there's support / ongoing development for the plugin), and of course I'd love to see the server-side checker come to feature-parity with WAVE (currently WAVE is showing a few things the server-side checker doesn't have [color contrast, etc.]) Keep up the great work!
When you insert an image into a post or page, consider providing a rich description for the caption that will improve the reading experience for everyone, but especially folks who can’t see the image. Be creative. Instead of “My son on his swing,” try “My son is playing on his favorite swing. His face is filled with pure joy on a beautiful Spring day. Perfection.” The goal here is to convey the feeling of the image.
The Department has assembled an official online version of the 2010 Standards to bring together the information in one easy-to-access location.  It provides the scoping and technical requirements for new construction and alterations resulting from the adoption of revised 2010 Standards in the final rules for Title II (28 CFR part 35) and Title III (28 CFR part 36).

Aloha Tatiana! I wish your questions had straightforward easy answers – and if you are government funded it kind of is. (See here: https://www.ada.gov/websites2_prnt.pdf) if you are not government funded, this is something that is currently being debated in the legal system. That being said, the WCAG 2.0 guidelines are a good set of guidelines to help protect yourself if you feel you should. (You can see more on WCAG here: https://www.yokoco.com/find-out-how-to-make-your-website-compliant/)
More than 1 billion people live with disabilities; over 57 million reside in the United States, many of whom are unable to participate in everyday activities, such as using computers, mobile phones, tablets, and similar technologies. Devices that should help to improve quality of life for disabled individuals often become a source of frustration due to the inaccessibility of websites. By making your website ADA compliant, you will gain a new and loyal revenue source, and minimize the possibility of legal action against your company.
Craig facilitates the execution of each project from start to finish, helping you convey your vision and bring it to life. Craig’s primary objective is to make certain that all of your needs are addressed throughout the project, from detailed technical specifications to assisting with collecting assets. This allows the staff of Quantum Dynamix to focus on what they do best; creating innovative work that meets your objectives.
Luckily, the international nonprofit World Wide Web Consortium (W3C) brings together smart people who develop open standards to ensure the long-term growth of the Web. They produce recommendations for making websites fair and equally accessible for the highest number of people possible. Their Web Content Accessibility Guidelines (WCAG) 2.1 offer clear guidance for web developers to achieve ADA compliance.
Case law has been the most helpful in illuminating the implications of the ADA for websites.There have been lawsuits involving companies like Expedia, Hotels.com, Southwest Airlines, and Target as defendants and primarily featuring accessibility organizations as plaintiffs. These cases had mixed results, but each helped clarify the ADA's jurisdiction on the web. 
The Americans with Disabilities Act (ADA) was first passed in 1990. Twenty years later, the US Department of Justice released an update called the 2010 ADA Standards for Accessible Design. These standards cover the design of physical spaces and have been interpreted to include web locations as well, so it can be difficult for the would-be accessible website designer to use them.