Difference between Darknet, Deep Web and Clearnet:

Clearnet/Surface Web - indexed by search engines like google and Bing.

Deep Web - contents are not indexed by standard web search engines.

Example telegram chats, WhatsApp messages, signal messages, messenger conversations, web mail, online banking, web forums etc. etc.

Dark Net/Dark Web - specialized software or knowledge that required access the communications.

Darknet most common network is Tor network here the URL ends in. onion

The famous case of silk road happened on Tor network.

There are others like i2p, freenet, zeronet etc. all of them use different software to access.

Below attached a picture of Tor network.

Note that the exit node of Tor is not encrypted