The type of list tag defines the type of list, duh. Numbered and bulleted are the most common ones.

Numbered — or ordered — lists are introduced with the tag <ol>. It works together with list item tag <li> nested within it. Every item you put within <li> element will be displayed with a number, depending on its position in the code. As you can probably guess, ordered lists are for cases where the order of items is important — for example, cooking recipes or driving directions.