Generally, at the pre-offer stage, an employer cannot ask questions that are likely to elicit information about a disability.
An employer may ask whether applicants can perform any or all job functions, including whether applicants can perform job functions "with or without" reasonable accommodations.
An employer may tell applicants what the hiring process involves (for example, an interview, timed written test, or job demonstration), and may ask applicants whether they will need a reasonable accommodation for this process.
If an applicant requests an accommodation for the hiring process (such as a request for the employer to reformat an examination), but the the need for accommodation is not obvious, an employer may ask an applicant for reasonable documentation about his/her disability.
As with reasonable accommodation requests made at any time throughout the hiring process or during employment, the applicant must disclose their qualified disability in order to receive the accommodation.