Would I need a permit to design a shed?

Okay, I am designing a shed for someone. She wants to turn her shed into a creative studio. I'm not building anything, so why would a permit be needed? I'm just redesigning the place. I'll be doing floor plans to make the space more functional. Electricity is already available. I'm just giving her a design, and from there we would contact a contractor. I'll let the contractor or architect know everything that I designed. Would I need a permit even though my part has nothing to do with labor, or the actual place being put together. (Also I'm located in central florida)