The ADA has four main components: (1) requirements for maintaining medical records and requiring medical testing, (2) an employer must reasonably accommodate disabilities, (3) an employer may not discriminate against an individual with a disability, and (4) an employer may not retaliate against someone who opposes discrimination of participates in protected activity.
In the context of employment, the ADA prohibits employers from taking disability into consideration in all aspects of the employment relationship—from hiring to firing and virtually everything in between. The law also requires employers to make reasonable accommodations for individuals with disabilities to help them do their job. Outside of employment, the ADA requires most public places, such as shops, restaurants, and movie theaters, to be accessible to those with disabilities. State and local laws can also provide further protections.

This title outlines the administrative processes to be followed, including requirements for self-evaluation and planning; requirements for making reasonable modifications to policies, practices, and procedures where necessary to avoid discrimination; architectural barriers to be identified; and the need for effective communication with people with hearing, vision and speech disabilities. This title is regulated and enforced by the U.S. Department of Justice.
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.