How to add the Nevada community property form to tax return that was just submitted?

[MonikaK1]

If you are married and file separate returns, and you live in a community property state, you and your spouse must each report half of your combined community income and deductions in addition to your separate income and deductions. Each of you are required to complete and attach Form 8958 to your return showing how you figured the amount you are reporting on your return. However, if you figured the correct amount but didn't include the form, you don't have to amend your return. You may eventually receive a notice asking for the form.

According to the IRS:

If you need to make a change or adjustment on a return already filed, you can file an amended return. Use Form 1040-X, Amended U.S. Individual Income Tax Return, and follow the instructions. 

You should amend your return if you reported certain items incorrectly on the original return, such as filing status, dependents, total income, deductions or credits. However, you don’t have to amend a return because of math errors you made; the IRS will correct those. You also usually won’t have to file an amended return because you forgot to include forms, such as W-2s or schedules, when you filed — the IRS will normally request those forms from you.

See IRS Publication 555 for more information.

On the appropriate lines of your separate return, list only your share of the income and deductions on the appropriate lines of your separate tax returns (wages, interest, dividends, etc.). The same reporting rule applies to registered domestic partners. For a discussion of the effect of community property laws on certain items of income, deductions, credits, and other return amounts, see Identifying Income, Deductions, and Credits , earlier.

Attach your Form 8958 to your separate return showing how you figured the income, deductions, and federal income tax withheld that each of you reported. Form 8958 is used for married spouses in community property states who choose to file married filing separately. Form 8958 is also used for registered domestic partners who are domiciled in Nevada, Washington, or California. A registered domestic partner in Nevada, Washington, or California must follow state community property laws and report half the combined community income of the individual and his or her registered domestic partner.

In some states, income from separate property is separate income. These states include Arizona, California, Nevada, New Mexico, and Washington. Other states characterize income from separate property as community income. These states include Idaho, Louisiana, Texas, and Wisconsin.