Just give your preparer the amount you invested in the opportunity zone fund and the date you invested. Also, be sure that you provide the capital gain you wish to have deferred by the investment. If you had multiple gains that occurred within 180 days of the investment ( Date of sale is the due date of tax return without extension for gains from partnerships). You can choose the gain that gets deferred. In most cases use the short term gains first. Also, note that the deferred gains do not need to be reduced by other capital losses. In the case where the state does not allow the deferral of gain, the tax preparer will also need to keep track of a different federal and state tax basis. The preparer will enter the deferral directly below the gain being deferred with a code of Z next to the deferral. Multiple gains can share in the same deferral.