If your Medicare Part D premium is not shown on your Form SSA-1099, then it was not deducted from your Social Security benefits. If you paid the Part D premiums separately, and you are itemizing deductions, you can enter the amount you paid under medical expenses.
In 2024 some Medicare Part D plans had zero premiums, so you might not have paid any Part D premiums in 2024.
Only Part B premiums are on your SSA-1099. Your Part D premiums are deductible if you itemize deductions. If you want to enter those costs, they are entered in the Medical Expenses section of Deductions and Credits.
When you sign up for Part D each year you have the option of having the premiums deducted from your Social Security benefits. If you select that option, the Part D premiums are shown on your SSA-1099 at the end of the year. If you do not select that option, the Part D premiums are not shown on your SSA-1099.