To complete the Request for Employment Information form (CMS-L564) when enrolling in Medicare Part B due to a SEP based on current employment, you should provide the name and contact information of your employer or the person responsible for reporting your wages to the Social Security Administration. You should also provide your Social Security number and the reason for your Special Enrollment Period. The form should be completed and returned to the Medicare Enrollment Center as soon as possible to avoid any delays in your enrollment.