┌─┐┌┬┐┌─┐┬ ┬ ┌─┐ ┌─╮ ┬ ┬
└─┐││││ ││ │ └─┐ ├┘┐ │╲│
└─┘┴ ┴└─┘└─┘ ┴ └─┘ ┴─┘ ┴ ┴ ○
International Standard Book Number (ISBN)
If you reach the point where you can sell your work, or maybe even to distribute it free of charge, you will need an ISBN.
The ISBN system is partly a public service required to enable the location an cataloging of books, and for major publishing companies and countries it is a source of revenue.
As a resident of a county with minimal publishing industry or interest I am able to provide ISBN as a publisher under somewhat relaxed conditions.