Learn when your job-based drug coverage qualifies as creditable so that you can know when to enroll in Part D drug coverage. Learn about Medicare enrollment, costs, supplemental coverage, and plan choices. This section has information about Original Medicare, Medicare Advantage, and Part D. Part D Part D Part D, also known as the Medicare prescription drug benefit, is the part of Medicare that provides prescription drug coverage. Part D is offered through private companies either as a stand-alone plan, for those enrolled in Original Medicare, or as a set of benefits included with a Medicare Advantage Plan. If you need to enroll in Medicare Part D for the first time, typically you will do so either during your Initial Enrollment Period (IEP), the Fall Open Enrollment Period, or if you qualify for a Special Enrollment Period (SEP). Additionally, you must: Have Part A Part A Part A, also known as hospital insurance, is the part of Medicare that covers most medically necessary hospital inpatient. To enroll in Medicare Part D prescription drug coverage, you must choose from private plans available in your service area service area The service area is the geographic area where a Medicare Advantage Plan or Part D plan provides medical services to its members. In many plans, the service area is where your network of providers is located. How to choose a Part D plan Make sure to look at. Part D Part D, also known as the Medicare prescription drug benefit, is the part of Medicare that provides prescription drug coverage. Part D is offered through private companies either as a stand-alone plan, for those enrolled in Original Medicare, or as a set of benefits included with a Medicare Advantage Plan. Part D Part D Part D, also known as the Medicare prescription drug benefit, is the part of Medicare that provides prescription drug coverage. Part D is offered through private companies either as a stand-alone plan, for those enrolled in Original Medicare, or as a set of benefits included with a Medicare Advantage Plan. Changing Part D coverage If you are in a nursing home, you are able to switch your drug coverage outside regular enrollment periods enrollment periods Enrollment periods are certain periods of time when you can join the Original Medicare program, or enroll in a Medicare Advantage Plan, Part D plan, or supplemental insurance plan (Medigap). Learn how Medicare Part D provides outpatient drug coverage through private plans, when to enroll, and how it works with other insurance. Learn about your options for removing your Part B late enrollment penalty if you think you have one by mistake.