Each August, the property appraiser sends a Truth in Millage (TRIM) notice to all property owners as required by law. This notice is very important — look for it in the mail! You’ll recognize it by prominent lettering, “DO NOT PAY – This is not a bill.” The TRIM notice tells you the taxable value of your property. Taxable value is the just value less any exemptions. The TRIM notice also gives you information on proposed millage rates and taxes as estimated by your community taxing authorities. It also tells you when and where these authorities will hold public meetings to discuss tentative budgets to set your millage tax rates. The Jefferson County Tax Collector will send each taxpayer a bill on November 1 of each year.

The State of Florida does not assess or collect property taxes; they are assessed and collected by locally-elected officials. If you have questions about your tax bill or unpaid taxes, contact your tax collector.

Property appraisers build the tax base by estimating the market value, or just value, of every property in the county as of January 1 each year. Just value is the amount a willing purchaser would pay a willing seller. Property appraisers also administer exemptions.
More Info: http://dor.myflorida.com/dor/property/exemptions.html