Starting from Notepad++ 7.5.x “Plugin Manager” is not bundled with this editor & you would find why and associated reasons here
So how do we have this “Plugin” configured for managing the plugins? Well the solution is pretty straight forward, download the latest version of the plugin manager from here
Please note, after downloading the plugin which is a zip archive, you need to extract it and there will be two folders, one for the Plugin Manager plugin & other one for the updater. Check the below image:
Note: The instructions given below are specific to 32-Bit version of Notepad++
Now, copy “PluginManager.dll” from plugins folder to “C:\Program Files (x86)\Notepad++\plugins” (default installation location, adjust to suite your environment)
Copy “gpup.exe” from “updater” folder to “C:\Program Files (x86)\Notepad++\updater” (Mandatory)
Now you are all set to start using Plugin Manager once again.