Missing Field "url" (optional) Structured Data Error

How To Fix Author Missing Field “url” (optional) Structured Data Error in Blogger ? Though this problem is optional but I want to do fix it.

The Author URL would be a link to a page about the author, if one exists.
If not, you could add profile pages to your site with a bio for each author and link to that.
But if no such page exists, you can;t have it.