Most workers have heard the term “reasonable accomodation” without understanding what it means according to state and federal law. If a worker qualifies as an individual with a disability, s/he may be entitled to a “reasonable accommodation” to continue to do his or her work. This rule applies both when starting a job or after something has happened to make the worker disabled.
In California, employers with five or more workers must provide the accommodation. Under federal law, employers need to have 15 or more workers. Typically, accommodation falls into two categories:

(1) an employee needs some kind of workplace setup to help with a disability, like someone with carpel tunnels syndrome may need an ergonomic desk and computer

(2) an employee needs to have flexible work hours or work at home so that they can get medical treatment. 
The kind and “reasonableness” of accommodation depends on the situation of both employer and employee. A large company may more easily spend more for a new chair and desk. The large company may have more flexibility to provide for different work hours or for working at home. And the employee’s disability may require a minor or a major accommodation.