Those instructions look really old. You report this income on the same form 1040 where you report your W2 income. You can report it as a scholarship or as "Other Income," in my many years of wild academia income the IRS never got pressed where I wrote down the income as long as I recorded it somewhere. 1040-ES is like a payment slip for people who make estimated tax payments. Have you already filed a federal tax return for 2023? Edit: I just saw your other comment, search for "scholarship income" instead of searching for a specific form. H&R block wants you to enter forms that you receive, like a W2. Then they output the 1040. But sometimes income isn't reported to you on a form. More on reddit.com

Pub 17 is designed to be that for individuals, but there are dozens of other pubs to provide more details: https://www.irs.gov/forms-pubs/about-publication-17 More on reddit.com

Form 1040 is the tax return you filed - if you look at the PDF you'll see it. Form 1040 is your personal federal tax return with different forms and schedules. This letter means there may be an issue verifying your earned income or federal taxes withheld. It's a pretty common hold for someone with Earned Income Credit on their return. If you can access your online IRS account, check your Wage and Income transcript for 2021. If you are married have your spouse check their transcript. Look for anything weird, like a W-2 not showing up on the transcript. Also look for typos - your Form 1040 Line 1 should equal the Wages from all W-2s Box 1, and Form 1040 Line 25a should equal the federal tax withheld from all W-2s Box 2. Then you can try contacting Taxpayer Advocate Service or your Congressional Representative's office for help. Waiting for IRS to tell you what the specific issue is can take a few more months. https://www.taxpayeradvocate.irs.gov/contact-us/ https://www.house.gov/representatives/find-your-representative More on reddit.com

If they e-filed the return and you didn't get a copy, your best bet is to get a Return transcript from your online IRS account, or try the Get transcript by mail option here: https://www.irs.gov/individuals/get-transcript This option only sends a copy to the mailing address on file, which is usually the mailing address on your most recently-filed tax return. If you've moved since then you should call IRS or send in Form 4506-T. https://www.irs.gov/forms-pubs/about-form-4506-t If you are applying through FAFSA there should be an option to automatically transfer the data from IRS, although it looks like they are changing the tools. More on reddit.com