If you already have your own ISBN, you can provide it to us to add to your book.
To provide an ISBN, mention it under Additional Notes when you publish.
Two things to note:
One ISBN per format edition. An ISBN uniquely identifies a particular format edition of a book — eBook, paperback or hardcover. To publish only under ISBNs you provide, we need an ISBN for each format under your plan.
ISBNs cannot be used before. If you’ve already used your ISBN to publish before, we may not be able to re-assign it. We’ll reach out to you if this happens.