How do I add a Florida license to Apple Wallet?

You cannot, at least not yet.

Florida does not yet support adding driver's licenses to the Wallet App.

click here ➜ https://learn.wallet.apple/id#states-list

and here ➜ Add your driver's license to Apple Wallet - Apple Support

Florida isn't one of the states that currently supports Apple Wallet. See: https://learn.wallet.apple/id#states-list

and

Add your driver's license to Apple Wallet - Apple Support

It does not appear that Florida has passed legislation to allow the license to be added to the Wallet. Some states are slow to support this new form of verification and others may want to use their own e-card software.

https://learn.wallet.apple/id#states-list