Your lawyer will simply prepare a list of documents that are important, and ask the other lawyer for them. Be prepared to have your spouse's lawyer ask you for a multitude of documents also. Be sure to cooperate in this request. It will save you money. Formal discovery involves interrogatories and requests for production of documents.
Interrogatories are an inexpensive method of gaining information and narrowing issues.
Either of you may send the other formal written questions which must be answered under oath within 30 days of their service. If interrogatories are served upon you and you don't respond, your spouse can obtain a court order to force you to respond. This is expensive and a foolish waste of money, so make sure you and your lawyer answer the questions completely. Another method in the formal process of discovery involves requests for production of documents. This is not a great deal different from the informal method, but like interrogatories, if there is no response, it can lead to court orders, sanctions, possible jail time and a big waste of money.