Editing WoW:AddOn (section)

=== Classic and Retail ===

With the addition of WoW Classic, around August 2019, the '_classic_' or '_retail_' folders are now the main WoW folders, which are inside the WoW install folder. Each of these folders are a nearly self-contained and distinct version of WoW themselves. 

* {WoW Install} (folder) - your WoW installation folder
** _classic_ or _retail_ (folder)
*** Interface (folder)
**** AddOns (folder)
***** MyAddOn (folder) - your addons own folder, must match the .toc name
****** ... addon files

From looking at this, you can see that the actual folder layout is almost exactly the same as before. The exception is that there is now an extra child folder under the WoW install folder, that then contains the specific game variant. Inside that game variant are the same folders that were under WoW the install folder before.