No! Florence is an incredibly walkable city. Everything you could want to do/see and or need is within a short walk.
Formal if you like, but please dress smart/comfy as it will be summer in Italy!
HOT.
The best way is to walk! Florence is incredibly walkable. If you don't feel like walking, there is a great taxi company that is similar to Uber. Download the app "it Taxi" before you go and use as needed!