Chapter 2: Overview of the Probate and Family Court in Family Law Advocacy for Low and Moderate Income Litigants, 3rd Edition 2018, has information about the process of "discovery."
Discovery is the way parties in a court action gather information from each other so they can build a strong case and improve their chances of getting the court to order what they need.
Discovery makes it possible to get information and documents from the other party. It also makes it possible for the other party to get information from you.
This chapter also has information about "mandatory disclosure," a procedure under which requires parties to give information to each other without having to ask for it. In some cases, you will not need to perform discovery beyond what mandatory disclosure requires.
In other cases, discovery is important to your case. Discovery is especially important when there are contested issues or assets.