LLC in Alabama or Florida?
Every state can have it's own advantages and disadvantages to registering your business in that state.
Forming an LLC in Florida would cost you less in the state filing fee; however, Florida requires LLC's registered in the state to file an annual report every May 1st, which the state charges $138.75 to file.
Forming an LLC in Alabama, on the other hand, would cost a little more to initially set up in terms of state filing fee, however the state does not require LLC's registered in the state to file an annual report; so this over time would save you money and time.
Without knowing the nature of your business, I can't tell if you would be required to register in a particular state. If you have a nexus in either state, such as an office, employees or if you conduct your business in person, then you are usually going to need to register in that state, respectively.