So my team started before we were registered and had received the notebook so we used a normal spiral notebook. Is that legal? Or will I have to put it in a standard issue notebook.
There is nothing particularly legal or illegal about notebooks, as rules about legality will all be found in the game manual and the official q&a. The guidance that you are looking for will be found by reviewing the judges guide, which you can find here: https://www.roboticseducation.org/resources_library/judge-guide/
Pay special attention to the engineering notebook rubric that you will find in the judges guide. To specifically answer your question, there is no requirement that any particular notebook be used. Using a bound engineering notebook which is handwritten has, in the past, given a team some bonus points on the rubric. Things are different this year, with the remote judging that goes on.