No, you’re only allowed to deduct donations made in the year of your tax return, except if you had a charitable carryover. If you itemize deductions, then your donations to qualified charities and non-profit organizations can be deducted in the year they were made.
For example, donations to Goodwill on January 2, 2020 and the Red Cross on December 31, 2020 would be deducted on your 2020 tax return. Learn more about deducting donations here.
You can amend up to the last three tax years to add contributions you made in previous years, but were missed when you filed. Learn more about amending your tax return here.