Form 1040X, Part III, Explanation of Changes (on page 2) is used to explain specific changes being made on the return and the reasons for each change.
Explanations should be easily understood. Clearly point out that the taxpayer qualifies for the change. For example, "taxpayer received another W-2 after they filed original return," or "taxpayer qualifies to claim child care expenses of $600 for their 10 year old dependent child, Form 2441 attached," or "taxpayer meets the qualifications to file as Head of Household instead of Married Filing Separately."
You can easily find out the status of a Form 1040X, Amended U.S. Individual Income Tax Return, using the Where's My Amended Return? tool on IRS.gov. It's available in English and Spanish, and tracks the status of the amended return for the current year and up to three prior years.
You can obtain a free transcript of your original or amended return from the last 3 years using the IRS2Go phone app, by calling 800-908-9946 and following the recorded instructions, or by sending a completed Form 4506T or Form 4506T-EZ, Request for Transcript of Tax Return, to the IRS. For a free copy of your original return, complete and mail Form 4506, Request for a Copy of Tax Return, to the appropriate IRS office listed on the form.