Should I amend my return if I accidentally put my charitable donations into the subtractions section rather than letting standard deductions account for it?

I thought the qualified charitable donations subtraction was for donations I made throughout the year, which I don't have a good record of. I learned my donations were lumped into my standard deduction, so I didn't need to fill that portion in, but now it says I need to mail in receipts for the donations. I'm unsure if I should try amending it, or if not mailing anything in would void my return.