I have two questions:
What is discovery process and how is it done?
Is there a good way to hide some assets prior to divorce?
Sorry to hear of your pending divorce.
Discovery is a process in a legal proceeding (i.e., not just divorce) during which each side gathers information from the other side. Each side is entitled to information that is relevant to the matters at hand, with few exceptions. An attorney would be better suited than me to explain all the reasons why particular information or amounts of information are not appropriate during the process.
Discovery can happen through interrogatories, admissions, depositions, and requests for document production.
Interrogatories are usually open-ended questions (e.g., a crude example is "List all the checking account numbers of accounts you've held in the past 5 years.").
Admissions are simple facts stated individually that the other side can admit or deny. A Request for Admissions is used to establish a foundation of factual circumstances that can later be used in court and in pleadings as a short-cut... it essentially says, "The parties both agree on these admissions, so no need to enter evidence on these facts."
Production of documents is literally that. A Request for Production of Documents may include tax returns, bank statements, etc.
Depositions are informal examinations made under oath and in person, prior to a court hearing. It gives the deposing party the ability to ask many questions of the other party. Usually, just about anything that has any remote relevance to the matter at hand is allowed. Depositions are often more useful than admissions or interrogatories, because a deposition doesn't give the other side much time to think and prepare an answer. Further, many more questions can be asked during a several hour deposition. Because the testimony is under oath, it's all admissable as evidence, and it essentially locks in the deposed party's answers (i.e., else they'd have to explain in court why their answer has suddenly changed).
As far as hiding assets, you should tread with caution. In some jurisdictions, a judge has discretion on how to split assets, especially if it discovers fraud. In one infamous case in California, a woman failed to disclose that she was holding a winning lottery ticket prior to filing for divorce. When the judge later learned that the wife didn't declare her winnings as community property, the judge gave the husband 100% of the winnings.
I'm sure there are some ways to help protect assets that are not community, but you'd need to consult with an attorney in your area for those best methods.
This website gives common sense advice that is not intended to act as legal guidance nor psychological guidance. The author is neither an attorney nor licensed psychologist. For specific legal guidance or specific psychological guidance, consult with a licensed professional.