My name is Ciarán, I'm a Shopify Support Guru.
In your admin if you head to Settings > taxes > click on United States it should say "County, municipal, and state taxes" and Florida should be present. Edit this to change the tax charged on customers in Florida.
To test this out, make a test order with your shipping location in Florida and the tax should be applied.
Here are some guides that may be useful:
Do one of these work for you? Let me know
All the best,
Ciarán H | Shopify Guru