Visit your local DMV to pick up an application for a handicapped parking sign. Many states also offer the form online for printing.
Contact and schedule an appointment with your doctor and inform her that you're applying for a handicapped parking permit. Many states require a doctor's approval in order to apply for the permit.
Complete the applicant portion in its entirety. Ask your doctor to complete the physician portion of the application.
Mail or drop off the application with the required fee at your DMV.