If your investing in Florida you will need a LLC registered in this state to trade properties however this may not be the case if your are buying investment property with the intention to hold it long term i.e. you maybe able to buy your long term holds in a foreign entity such as a Wyoming ,Delaware or Nevada LLC. This is something you will need to discuss with a USA attorney. Also in Florida something to be aware of is a single member LLC is treated as a disregarded entity thus providing you with little to no protection therefore it is recommended to have a dual member LLC. Again you need to discuss this with your USA attorney.
Every State has different requirements and rules so first you need to decide where you will be investing and how that states rules apply to your situation,whether you will be trading or holding property so you can decide your next step.