Once you realize you made a mistake or forgot to include an important piece of information on your tax return, how you handle it depends on the situation. For instance, if you entered an incorrect Social Security Number (SSN) for yourself, your spouse, or a dependent, you need to fix it.
If you missed an income item that affects the amount of tax you owe, you also need to tell the IRS before they discover it. If they find it before you inform them of the mistake, they may penalize you.
If you found a small item you should have deducted, like a $5 receipt, there’s a good chance you don’t need to do anything. It’s probably not worth the trouble as more than likely it won’t have a huge impact on your return.
Reach this article for more information on when and how to amend your return.