Aloha Tatiana! I wish your questions had straightforward easy answers – and if you are government funded it kind of is. (See here: 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:
Another federal agency, the Architectural and Transportation Barriers Compliance Board (ATBCB), also known as the Access Board, issues guidelines to ensure that buildings, facilities and transit vehicles are accessible to people with disabilities. The Guidelines & Standards issued under the ADA and other laws establish design requirements for the construction and alteration of facilities. These standards apply to places of public accommodation, commercial facilities, and state and local government facilities.
Title II of the ADA prohibits discrimination against qualified individuals with disabilities in all programs, activities, and services of public entities. It applies to all state and local governments, their departments and agencies, and any other instrumentalities or special purpose districts of state or local governments. It clarifies the requirements of section 504 of the Rehabilitation Act of 1973, as amended, for public transportation systems that receive federal financial assistance, and extends coverage to all public entities that provide public transportation, whether or not they receive federal financial assistance. It establishes detailed standards for the operation of public transit systems, including commuter and intercity rail (e.g., AMTRAK).
Level AA is a little more significant, and makes sites accessible to people with a wider range of disabilities, including the most common barriers to use. It won't impact the look and feel of the site as much as Level AAA compliance, though it does include guidance on color contrast and error identification. Most businesses should be aiming for Level AA conformity, and it appears to reflect the level of accessibility the DOJ expects. 
Because the ADA establishes overlapping responsibilities in both EEOC and DOJ for employment by State and local governments, the Federal enforcement effort is coordinated by EEOC and DOJ to avoid duplication in investigative and enforcement activities. In addition, since some private and governmental employers are already covered by nondiscrimination and affirmative action requirements under the Rehabilitation Act of 1973, EEOC, DOJ, and the Department of Labor similarly coordinate the enforcement effort under the ADA and the Rehabilitation Act.
Tennessee v. Lane[80], 541 U.S. 509 (2004), was a case in the Supreme Court of the United States involving Congress's enforcement powers under section 5 of the Fourteenth Amendment. George Lane was unable to walk after a 1997 car accident in which he was accused of driving on the wrong side of the road. A woman was killed in the crash, and Lane faced misdemeanor charges of reckless driving. The suit was brought about because he was denied access to appear in criminal court because the courthouse had no elevator, even though the court was willing to carry him up the stairs and then willing to move the hearing to the first floor. He refused, citing he wanted to be treated as any other citizen, and was subsequently charged with failure to appear, after appearing at a previous hearing where he dragged himself up the stairs.[81] The court ruled that Congress did have enough evidence that the disabled were being denied those fundamental rights that are protected by the Due Process clause of the Fourteenth Amendment and had the enforcement powers under section 5 of the Fourteenth Amendment. It further ruled that "reasonable accommodations" mandated by the ADA were not unduly burdensome and disproportionate to the harm.[82]
This past September marked the first time a judge ruled that the ADA applies even to businesses without a physical location. Scribd, an e-book subscription service is considered to provide "a place of public accommodation." Their services are not accessible to blind persons because they cannot be read with a screen reader. The judge reasoned, "Now that the Internet plays such a critical role in the personal and professional lives of Americans, excluding disabled persons from access to covered entities that use it as their principal means of reaching the public would defeat the purpose of this important civil rights legislation."
Decided by the US Supreme Court in 2002, this case [74][75] held that even requests for accommodation that might seem reasonable on their face, e.g., a transfer to a different position, can be rendered unreasonable because it would require a violation of the company's seniority system. While the court held that, in general, a violation of a seniority system renders an otherwise reasonable accommodation unreasonable, a plaintiff can present evidence that, despite the seniority system, the accommodation is reasonable in the specific case at hand, e.g., the plaintiff could offer evidence that the seniority system is so often disregarded that another exception wouldn't make a difference.
What do you want your website to look like? Consider websites that are similar to the one you’d like to build, ideally in the same industry or serving similar types of customers. Build a set of examples of types of pages, design aspects, and website features that you can hand off to the web designer — the person you hire should have experience creating websites with the features you want. If they don’t have the right skill set, they’re not the right pro for you.
The need to make websites, mobile apps, and other online properties accessible to all is only going to increase as time moves on. Smart business owners will do well to get in front of this issue and make sure that their websites are ADA compliant now so that all their customers have the equal access to the resources they offer. Not just because they want to avoid a lawsuit or government action, but because it’s the right thing to do.
Once you have been hired and started work, your employer cannot require that you take a medical examination or ask questions about your disability unless they are related to your job and necessary for the conduct of your employer's business. Your employer may conduct voluntary medical examinations that are part of an employee health program, and may provide medical information required by State workers' compensation laws to the agencies that administer such laws.