It’s a common misconception but it is in fact illegal to claim other’s donations as donations by the corporation, and it’s not too likely that very large organisations would do that. Of course, it’s possible they’re breaking the law. It is also irritating. Why doesn’t the multibillion company just make the donation instead of harassing me.

https://taxpolicycenter.org/taxvox/who-gets-tax-benefit-those-checkout-donations-0

The store serves only as a collection agent for your gift. Assuming the business is following the law, it will not include your donation as part of its business receipts, or income, nor will it claim the charitable gift as an expense.  In other words, your gift has zero impact on the store’s income taxes.