I have a degree in mechanical engineering and am licensed as a Professional Engineer in two states. I've held both licenses for over 20 years. The short answer to the original question:
Each state has a different legal definition of what constitutes the practice of "engineering, who may call themselves an "engineer", and how to get to that status. For the state of Florida, I would start to seek understanding here:
https://fbpe.org/legal/statutes-and-rules/
I'm not going to get into the whole debate of who should be allowed to call themselves an "engineer"...