The phrase "website address" refers to the unique location or name that is used to find and access a specific website on the internet. It's like a digital code or a signpost that helps people navigate to a particular website. Full definition
If you started your blog before your book was published, put your blog's website address on your book's back cover. (wiseinkblog.com)
Here is our listing with website address, telephone number or email address where provided. (belize.com)
The same holds true for including website addresses in a printed edition of a book (the chief reason I'm not, save for a few exceptions). (discoveringloveonline.com)