To be protected under the ADA, you must have, have a record of, or be regarded as having a substantial, as opposed to a minor, impairment. A substantial impairment is one that significantly limits or restricts a major life activity such as hearing, seeing, speaking, walking, breathing, performing manual tasks, caring for oneself, learning or working.
If you are applying for a job, an employer cannot ask you if you are disabled or ask about the nature or severity of your disability. An employer can ask if you can perform the duties of the job with or without reasonable accommodation. An employer can also ask you to describe or to demonstrate how, with or without reasonable accommodation, you will perform the duties of the job.
Most recently, however, pizza chain Domino's has been brought under suit for their website not being accessible for specialty ordering. The U.S. Supreme Court refused to review the case, instead upholding the decision of the 9th U.S. Circuit Court of Appeals who said the “alleged inaccessibility of Domino’s website and app impedes access to the goods and services of its physical pizza franchises—which are places of public accommodation.”