When to use serif fonts
Serif fonts contain extra flourishes at the ends of the letters to create an embellished, unified look much like the typesetting found on an old-fashioned typewriter. Fonts with serifs are especially useful for print, as they are more readable and allow the eye to tell the difference between letters when they’re close together. This makes them especially helpful when you have to deliver a large amount of text.
Serif fonts create a visual guideline for the eye to follow, making large paragraphs easy to read and scan.