In box 3 of SSA1099 these is a medicare deduction, where does this deduction get recorded?

On the same screen you enter the SSA-1099.  This is from last year but should look the same.   Are you entering the SSA-1099 in the right spot?

The Medicare premiums paid is entered by the TurboTax program on Schedule A as an itemized medical deduction.

Health care insurance premiums and other medical expenses that you paid with out of pocket funds are an eligible medical expense that you can deduct using Schedule A for itemized deductions. However, only your total medical expenses that are greater than 7.5% of your Adjusted Gross Income (AGI) can be deducted. Your total itemized deductions reported on Form 1040 Schedule A must be greater than the standard deduction for your filing status to have any tax benefit.

Standard deductions for 2021

• Single - $12,550 add $1,700 if age 65 or older
• Married Filing Separately - $12,550 add $1,350 if age 65 or older
• Married Filing Jointly - $25,100 add $1,350 for each spouse age 65 or older
• Head of Household - $18,800 add $1,700 if age 65 or older