Medicare Part D plans, which provide prescription drug coverage, are offered by private insurance companies with a Medicare contract. (It is also possible to receive prescription drug coverage through a Medicare Advantage Plan or a Medicare Cost Plan that offers prescription drug coverage)
Medicare Part D is an optional benefit. However, if you do not enroll when you are first eligible and do not have existing equivalent drug coverage, you may have to pay a premium penalty if you enroll at a later time.
Each Part D plan is different. Each can cover different drugs and have different costs.
To find and compare Part D plans, you can also go to Medicare.gov.ype your paragraph here.