Also called the General Homestead Exemption, this exemption is for individuals who own and occupy their property (as their primary residence) as of January 1st of the tax year. You can apply for this exemption anytime during the year. 
Once you apply for this exemption (application can be found here), it will remain in effect until the property transfers ownership.
This exemption reduces the real estate value by $6,000 or the increase above the 1977 EAV, whichever is less. 

Please contact the Winnebago County Supervisor of Assessments Office (815) 319-4460 with any questions.