Getting the Right Accommodations
Colleges and universities are required to provide reasonable accommodations to qualified students with disabilities. Each school may vary on what constitutes as acceptable documentation of a disability and what is considered a reasonable accommodation.
Consequently, it is important to compare the services offered by each college you consider, review your necessary accommodations, and complete the intake process with each college's campus Disability Services office. There are many differences between services provided in high school and those available in college. Colin Donovan, Disability Specialist at Bellevue College, recommends reviewing resources like "Differences between High School and College Accommodations for Students with Disabilities".
Many colleges require that the documentation be prepared by a doctor, psychologist, or other qualified diagnostician. Since documentation is used not only for academic accommodations, but also in housing, transportation, and other areas, it should include a diagnosis of your disability and how your disability impacts your major life activities. Although your individualized education program (IEP) or Section 504 plan from high school may help identify services that have been effective for you, it is generally not sufficient documentation. Discussing documentation with colleges while you are still in high school will allow you time to gather what you need. Submit your documentation early so that staff can notify you of any outstanding requirements for the accommodations you request.
Example policies and procedures from 2-year and 4-year institutions around the United States can be found at Typical Policies and Procedures. The rights and responsibilities of faculty, campus services, and students with disabilities can be found at Rights and Responsibilities.
For more information, check out Preparing for College: An Online Tutorial.