I got a letter from IRS that they adjusted my tax return...

[AustinTS]

Your notice or letter will explain the reason for the contact and give you instructions on how to handle the issue. The IRS might be informing the taxpayer of a correction that has been made or you owe taxes. Call the IRS at the toll free number on the top right corner of your notice. Please have your paperwork ready when you call. You can also call 1-800-829-1040

The IRS sends notices and letters for the following reasons

• You have a balance due.
• You are due a larger or smaller refund.
• We have a question about your tax return.
• We need to verify your identity.
• We need additional information.
• We changed your return.
• We need to notify you of delays in processing your return.

Check out this IRS tool to search " Search Individual Notices and Letters"
https://www.irs.gov/individuals/irs-notice-or-letter-for-individual-filers