In a very simplified way I think of these game versions like this.
In a nutshell.
Wow Retail. The most modern version of the game with all expansions and quality of life improvements, and Wow Tokens so you can buy in game gold with real world cash.
Wow Classic. The original version of 2004 with a few quality of life improvements, Nostalgia abounds here, along with a grindy slow progression. You earn what you gain the hard way. No Wow Tokens either. No Dungeon finder either.
Wow Classic Wrath of Lich king. Stands somewhere between retail and classic. Has Wow
Tokens.
Wow classic Hardcore. This is classic with character permadeath.
That’s just my opinion and I leave a more comprehensive explanation to others.