Customizing Border Page

I need to customize the border of my HTML page.

I really need to learn how to border this style:

How can I start looking and studying about the customization of these style borders? Is there any service of this type that I could purchase the html/css code, for example?

What is the name of this border style?

Solution

I would take a look the CSS property "border-image" and at this article. Might lead you closer to your goal. https://css-tricks.com/almanac/properties/b/border-image/