Many people find out about the warrant when a bail bond company in Bunnell, Palm Coast, Flagler Beach, Crescent City, East Palatka, Georgetown, Florahome, Hollister, Interlachen, Lake Comoo, Palatka, Pomona Park, San Mateo, Satsuma, Welaka and or Melrose FL, sends them a postcard that says "Notice of Active Arrest Warrant" in the mail.
If the warrant involves a failure to appear (especially after you were issued a "notice to appear") or a warrant issued in connection with a violation of probation, then you should contact an attorney to discuss your options.
You can also perform a local search in the county in which you think the warrant was issued. The website for the sheriff's office in each county maintains their warrant or wanted person search feature.