As you learned in the Sandboxes, talk pages, and watchlists training, a “sandbox” is your personal wiki page where you can practice editing, plan out work, draft articles, or just experiment.

Think of your sandbox as a replica of a blank Wikipedia article. All of the same tools are available for you to use.

Anyone can still see your sandbox, so it's important that the content you put there isn't something you don't want people to see. Also, don't copy and paste things there that might violate copyright rules.