Wax tablets were very common for information that didn’t need to be actually stored, like jotting down notes or making lists. Information that actually needed to be preserved was typically written on parchment or papyrus (or metal or stone, if it was particularly important to preserve) - papyrus, even, was sold by grade, with the lowest grade being used for wrapping.

Quill pens and reed pens were both in use by the Romans, though quill pens usually had the actual feathers removed, because it’s pointless to keep them. That’s less distinctive though, so we can give that a pass on artistic license.