Below is a short list of the types of information you will need to be prepared:
1. Personal financial information such as all recent bank account and credit card statements, recent investment and retirement account records, and pay stubs / pay advices, for you and your spouse.
2. Tax returns for at least the prior three (3) years, both personal and business. Tax returns can show not only income, financial condition, and asset depreciation but also possible marital tax assets like over paid tax liability or loss carry forwards that need to be addressed in property division. More commonly, they will show marital debts, such as unpaid taxes.
3. If your spouse is self employed or holds an interest in a closely held company or LLC, the business records, in particular the recent bank statements, tax returns, and organic financials (quick books data for example) of the company, is highly valuable. See if your spouse will voluntarily provide this information.
4. Mortgage or leasing information for your marital residence or any other residence owned or leased by you and your spouse. And any other documents showing any marital debts.
5. A list of the assets owned or debts owed by you and your spouse, both individually and jointly, whether separate or marital. Any loan applications you or your spouse submitted in past few years can be highly valuable as these usually contain credible statements of assets.
6. A list of all historic expenses for the marital household for the past two years. (All mortgage, tax, utility and upkeep expenses).
7. A list of all historic child care and extra curricular expenses for all children for the past two years. (You need to know the average monthly cost for the children, on a historic basis).
8. A list of your historic out of pocket medical expense for the entire family for the past two year.
9. Obviously any prenuptial or post nuptial agreements but also any other legal documents that might be relevant such as insurance policies (in particular any whole or variable life policies that might have a cash value), trusts, copies of LLC operating agreements, business records, etc.
10. Any documents (admissions, pictures, video or audio recordings) that would prove domestic abuse, adultery, or any other fault or wrongdoing of your spouse that may be relevant to your divorce.
If you do not have this information, and your spouse will not openly share this information (for example accounts that are only in his or her name), then you may have no choice but to file a contested action. (Your spouse will be required to produce all this information in discovery).