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/)
State and local governments will often post documents on their websites using Portable Document Format (PDF). But PDF documents, or those in other image based formats, are often not accessible to blind people who use screen readers and people with low vision who use text enlargement programs or different color and font settings to read computer displays.
Upon discovering issues faced by disabled government employees and the public, revisions to section 508 were made. The issues that were uncovered involved websites, documents, and software programs. As of January 2018, the updated 508 standards require all federal agencies and contractors to create web content accessible to all. The updated standards also include Website 508 compliance.
The Department of Justice (DOJ) has specifically stated in rulings that websites should be designed so they are accessible to individuals who have vision, hearing, and physical disabilities. There’s a growing body of case law where the DOJ required companies to provide an ADA compliant website and levied hefty penalties when sites failed to measure up.
This title requires telephone and Internet companies to provide a nationwide system of interstate and intrastate telecommunications relay services that allows individuals with hearing and speech disabilities to communicate over the telephone. This title also requires closed captioning of federally funded public service announcements. This title is regulated by the Federal Communication Commission.
Another important consideration is that the ADA does not allow businesses to simply provide an alternative such as a phone number. Lastly, include accessibility issues as part of your website and mobile strategy. When new technologies are implemented or pages added, part of the process should include the implications for persons with disabilities.
Talk to your web designer about other techniques that will make your site more user-friendly for people with disabilities. Worried that’s not in your budget? Consider the fact that DOJ fines start at $75,000. And it's still yet to be determined if a non-compliant website is liable for one fine or will be charge per page for each violation. As the recent lawsuits illustrate, though, settlements quickly add up into the millions.