The best way to create HTML borders is to actually use CSS (Cascading Style Sheets). Using CSS, you can create a border around any HTML element.
There are a range of CSS properties that you can use to define borders but the shorthand border property is the most concise way.
Below are some examples of what you can do with HTML, borders, and CSS.
You can combine different border types and styles for each side of the HTML element.
Inline, Embedded, or External?
All of the above examples use "inline" styles to create the borders. You can also use "embedded" style sheets or "external" style sheets. In fact, embedded style sheets are more powerful than inline styles. And external style sheets are more powerful than embedded style sheets.
Use embedded style sheets if you need to apply the same border to multiple objects on the same page. Use external style sheets if you need to apply the same border to multiple objects on multiple pages (or across your whole site).
For more info, check out the various border properties on the CSS Properties list.