TurboTax automatically uses the standard deduction for you unless you enter enough itemized deductions to exceed your standard deduction, or unless you "force" itemizing or file married filing separately and are required to itemize because your spouse itemized. Look on line 9 of your Form 1040 to see your standard deduction.
PREVIEW 1040
https://ttlc.intuit.com/questions/1901539-how-do-i-preview-my-turbotax-online-return-before-filing
Click on Tax Tools on the left side of the screen. Click on Tools. Click on View Tax Summary. Click on Preview my 1040 on the left side of the screen.
2019 Standard Deduction Amounts
Single $12,200 (+ $1650 65 or older)
Married Filing Separate $12,200 (+ $1300 if 65 or older)
Married Filing Jointly $24,400 (+ $1300 for each spouse 65 or older)
Head of Household $18,350 (+ $1650 for 65 or older)
Look on line 9 of your 2019 Form 1040 to see your itemized/standard deduction amount