
The IRS would tell you yes, keep receipts for literally everything if you’re itemizing, because you could be audited. But for donations less than $250, a bank statement, credit card statement, etc is sufficient. If you’re rounding up I doubt they’re auditing you based on donations less than $1 (not tax advice!). For $250+ you need a receipt specifically from the organization. H&R Block has a page on this https://www.hrblock.com/tax-center/filing/adjustments-and-deductions/charitable-donations/