Snapchat allows users to add captions, drawings and filters to their photos and videos (also known as "snaps"). Unlike other messaging apps, you can view snaps for a maximum of 10 seconds, and then it's gone for good. Anything shared through the service self-destructs, leaving no evidence that it existed.
If you want to join the Snapchat craze and learn the basics, check out this step-by-step guidance.