If you are required to itemize on your Federal return, or if Itemized Deductions on your Missouri return will bring you a larger tax benefit than the Standard Deduction, TurboTax will automatically use Itemized Deductions for your Missouri return.
The Standard Deduction amounts for Missouri are as follows:
Single or Married Filing Separate - $12,000
Head of Household - $18,000
Married Filing Combined or Qualifying Widow(er) - $24,000
Itemized Deductions: If you itemized on your federal return, you may want to itemize on your Missouri return or take the standard deduction, whichever results in a higher deduction. If you were required to itemize on your federal return, you must itemize on your Missouri return.
https://dor.mo.gov/forms/MO-1040%20Instructions_2018.pdf
