I have included a link to Rule 4-7.21 Firm Names and Letterhead, for your edification. 

Your law firm name can take many forms, all a variation of:

 Law Offices of Mary Smith;

 Mary Smith, Esquire;

 The Smith Law Firm;

 The Smith Law Center.

All of these are acceptable and do not require a fictitious name registration because the name of the lawyer is in the name of the firm. 

If you should choose a trade name such as "The Immigration Law Center," or "The Ticket Clinic," then you would have to ask for a review of the proposed trade name in writing to the Ethics & Advertising Department of the Florida Bar.  Call them first at (850) 561-5780, if you should decide on a trade name. They might be able to help you over the phone. 

If you choose a trade name, you would need to do a fictitious name registration.

For your edification, I have also attached a hyperlink to the Handbook on Lawyer Advertising and Solicitation.