The EEOC elaborates on what "reasonable accommodation" means and who is entitled to receive it. For example, the right to reasonable accommodation is available even to part‑time or probationary employees. The Guidance covers the form and substance of a request for accommodation and an employer's ability to ask questions and seek documentation after a request has been made.

Generally, the disabled individual, or someone on his or her behalf, must inform the employer that an accommodation is needed, but the request can be made in plain English, without having to mention the Americans with Disabilities Act (ADA) or use the correct legal buzzwords. The request should begin an informal dialogue to identify the person's needs and a suitable accommodation. If the disability or the need for accommodation is not obvious, the employer may ask for reasonable documentation to establish the disability and the resulting functional limitations.

There are three categories of reasonable accommodations. They include modifications or adjustments to (1) the job application process; (2) the work environment or the circumstances in which a job is customarily performed; and (3) policies that set out the benefits and privileges of employment.

The Guidance emphasizes that an employer should assess the need for accommodations for the job application process separately from those that may be needed to perform the job. For example, an employer must avoid any tendency to exclude a qualified individual from the application process because of speculation by the employer that it will not be able to provide reasonable accommodations necessary for satisfactory job performance.

The Guidance goes into detail about some of the forms of reasonable accommodation, especially regarding the work environment and how a job is performed. A partial list of accommodations includes: making existing facilities accessible; job restructuring; part‑time or modified work schedules; acquiring or modifying equipment; and reassignment to a vacant position. The Guidance says that an employer is required to give a vacant position to a disabled employee who requests reassignment to that position and has the minimum qualifications for it, even if other more qualified individuals have applied.

There are limits to what the ADA requires of an employer that receives an accommodation request. For example, an employer cannot be forced to eliminate an essential function of a position, such as one of its fundamental duties. Nor does an employer have to lower qualitative or quantitative production standards that are applied uniformly to employees with or without disabilities. The employer may choose among several reasonable accommodations as long as the selected method is effective in allowing the individual to perform the essential functions of the position.

The most significant exception to the duty of accommodation is undue hardship on the employer. The undue hardship issue concerns quantitative, financial, or other limitations on an employer's ability to provide reasonable accommodation. The focus is on the resources and circumstances of the particular employer in relationship to the cost or difficulty of providing a specific accommodation, but the required considerations go beyond a rigid cost‑benefit analysis. Excessive costs can lead to a finding of undue hardship, but so can the fact that a requested accommodation is unduly extensive, substantial, or disruptive, or the fact that it would fundamentally alter the nature or operation of the business.