Directly taken from:
Beginning Graphic Design: Typography
Have little strokes called serifs attached to the main part of the letter.

Classic Look
Good for Traditional projects
Print publications, magazines and newspapers.
Don’t have little strokes. French for “without serif”

Clean and modern than serif fonts.
Tends to be easier to read on computer screens - including smartphones and tablets.
These come in many different styles, some include:

Decorative nature; Best for small amounts of texts
Ex: Titles, Headers, Graphic-heavy designs.