The location of XML tools has changed slightly since this question was first asked.
I am currently using Notepad++ v7.8.6
New location is:
- Plugins tab
- Plugins Admin...
- Plugins Admin dialog appears with Available plugins tab as the default
- Scroll to the bottom and check the XML Tools checkbox
- Click Install button in top right of the dialog
This will close Notepad++ while it installs and then restart it automatically.
Then there are a couple keyboard shortcuts to beautify the XML:
- Pretty Print: Ctrl + Shift + Alt + B
- Pretty Print (indent attributes): Ctrl + Shift + Alt + A
To see more XML Tools options:
- Plugins tab
- XML Tools option