No, you are not required to get a Medicare Part D plan. These Medicare plans for prescription coverage help pay for medications you need. It's optional and offered to everyone with Medicare.
However, even if you don’t take prescription medications now, you may want to consider getting Medicare prescription coverage. If you choose not to get it when you’re first eligible, and if you don’t have other prescription coverage (like from an employer or union), you may have to pay a late enrollment penalty if you join a plan later.
Read about your Medicare prescription coverage rights.