In most Family Law matters at some point you will need to prepare an Affidavit of Financial Information. This is essentially a snap shot of your financial status at that point in time, providing your monthly living expenses, your monthly income, and your debts.
You must also include a copy of your last several paycheck stubs, showing your gross and net income, and deductions. Often the information must be deciphered, to identify what a particular deduction is for, i.e., health insurance, life insurance, short or long term disability, 401(K) or other retirement, etc.
You must also attach copies of your prior three years tax returns. My suggestion would be to include your W-2's, especially if any of the returns were joint returns, so your annual income can be more readily identified.
Maintaining your personal records in an orderly manner will assist you when you have to prepare an Affidavit of Financial Information.