If you are purchasing an ISBN number from BookBaby, you will be given the option to choose the placement on the back cover during check out if you are supplying print ready files. If you are getting design, our designer will place that on there before sending you proofs.
We will also add it to your copyright page or title page if you leave a line that reads “ISBN“ anywhere on the copyright page. Putting the placeholder in an irregular place like the back of your book is not guaranteed to be spotted during our check.
As long as the fonts in your book are embedded, we will have no problem entering the ISBN in the same font used in your placeholder. If your fonts are only subset, a partial embedding, we may not have the characters available to make the change and we could fail it back for you to make the addition.