You will apply for a Florida Security Guard License with an application:
Class D Security Officer License Application.
The steps to becoming a Security Guard in Florida is similar to a lot of other states: you need to meet basic requirements such as age, language proficiency, and other usual security licensing requirements of this nature.
Furthermore, to get a Security Guard license in Florida, you need to take a government approved FL Security Guard licensing course:
This is a 40hr hour security training course.