There's a law in the United States that dictates how earnings from cover songs need to be shared with the original songwriter. If you're interested in the details, click here.
The good news is that DistroKid makes easy to upload covers, so easy that you never have to think about it. Just click the box on our upload form specifying that it's a cover song, and for a small fee ($12 per cover song, renewed annually) DistroKid will automatically withdraw the legally required amount from your earnings (usually 9.1 cents per sale in the U.S.) and send it to the original songwriter.