First, make you you’ve set up contact, tax, and banking information in Agreements, Tax, and Banking.
Second, download the latest version of iTunes Producer. After you sign in to iTunes Producer, you will see the Template Chooser window. On this window, click the Choose button to create a new book package. Add the metadata and pricing for the book, the book file and then click Submit to submit your book for review.
iTunes Producer requires:
App-specific passwords are required if your Apple ID is protected with two-step verification or two-factor authentication. If you have two-step verification enabled, you may see these two notifications:
Please sign in with an app-specific password. You can create one at appleid.apple.com.
Sign in with the app-specific password you generated. If you forgot the app-specific password or need to create a new one, go to appleid.apple.com.