What is ISBN number?

An International Standard Book Number (ISBN) is a unique 13-digit code that is assigned to every published book. The ISBN is used to identify and track books for sale, and it is required in order to sell a book through most retail channels.
To apply for an ISBN, you will need to complete the application process through your local ISBN agency. In the United States, the ISBN agency is Bowker. You can apply for an ISBN online through the Bowker website.
To apply for an ISBN, you will need to provide the following information:
- Title and author information
- Format of the book (print, ebook, audiobook, etc.)
- Dimensions and page count of the book
- Publisher information (if applicable)
- Language of the book
There is a fee to apply for an ISBN, and the cost will vary depending on the number of ISBNs you need and the country in which you are located.
It is important to note that ISBNs are typically assigned to individual editions of a book, so if you make changes to the book and republish it, you may need to apply for a new ISBN.