I filed my taxes already but now I want to contribute to my IRA, do I need to amend my return?

[macuser_22]

If a Traditional IRA - yes,  If a Roth - No.

[RayW7]

Yes, you will need to file an amended return. However the savings may be worth your time. 

Contributions to a traditional individual retirement account can be tax-deductible in the year you make them. Different IRS rules on IRA contributions apply to differing situations. However,

• You can generally deduct the full amount of an IRA contribution if you and your spouse aren't covered by retirement plans at work.
• If you and your spouse are covered, your contribution might be limited based on your adjusted gross income.

For example, if you are in the top tax bracket of 37% and make a $6,000 deductible contribution—the maximum for 2020—you can save as much as $2,220 in taxes based on 2020 tax rates. Best of all, unlike most tax-saving strategies that must be in place by December 31, you can contribute to an IRA all the way until tax filing day, typically April 15.

-follow these links for more information-

Video: How to Amend Taxes that Are Already Filed - TurboTax ...