Amazon KDP will provide a barcode for your book if you don’t have one. It will automatically upload it on the back of your cover. You can provide your own barcode and place it on the back cover before uploading your book cover to KDP.
The barcode that will print on your cover depends on which of the following three options you select when creating a cover:
You must update your cover file to add or remove a barcode if you want to change the barcode that prints on your cover.