The terms deep web and dark web are often used interchangeably, but they are not the same thing. The deep web simply refers to anything on the web that can’t be found using a search engine. This means anything behind a paywall, anything that is password protected, or anything that is dynamically generated on the fly and doesn’t have a permanent URL — all of these things are said to comprise the deep web because they don’t exist at the surface of the web.
You actually access the deep web routinely, every day. The emails in your Gmail account, your online bank statements, your office intranet, direct messages in Twitter, photos you’ve uploaded to Facebook and marked as private. These are all the deep web.
Neither the deep web nor the dark web can be indexed, but not all that cannot be indexed is the dark web. For purposes of this question, I assume you want the dark web – that much-hyped, mysterious place that the media would have you believe is a wretched hive of scum and villainy where you’d be well-served to shoot first if you hope to survive.
Activists will tell you it’s our last, best hope for privacy and free speech, all alone in the night.

These sites may contain links to illegal services and are provided for informational purposes only. If you’re scammed or get yourself into trouble, your recourse against the people you’ve dealt with is likely to be limited at best.