Property taxes are an itemized deduction. The Free version of Turbotax does not support itemized deductions. But before you upgrade to a paid version, consider that your property tax may not provide a tax benefit. To get a tax benefit from itemized deductions, all of them added together must be more than your standard deduction.
2016 Standard Deduction
Taxpayer under 65, not claimed as a dependent
$6,300 for Single
$12,600 for Married Filing Jointly, or Qualifying Widow(er) with dependent child
$9,300 for Head of Household
$6,300 for Married Filing Separately
For over 65 or blind, add $1,250 for each instance or add
$1,550 each instance if single and not a surviving spouse.