You may have to authenticate with either the admin or the user password before you can paste the file. Move the file to one of the following locations, based on how you want to install it.
This folder is located in the Library folder. In order to install a plugin in QuickLook, you have to move it to the QuickLook folder. The process isn’t complicated for either one so take that into account. Once extracted, you need to decide how you want to install the plugin i.e., system-wide, or just for the current user. In that case, you can extract it with the built-in Archive utility on macOS. The plugin file you have might have downloaded as a zipped file.
