To Indent a XML file in notepad++, TextFX > TextFX HTML Tidy > Tidy Reindent XML
If the TextFX menu does not exist, you need to download & install the plugin. Plugins->Plugin Manager->Show Plugin Manager and then check the plugin TextFX Characters. Click ‘install,’ restart Notepad++.
libTidy.dll might not be included in the new version of NPP.
Solution is to download the 5.9 zip, then
copy one of the following folders:
ansi\plugins\Config\tidy or Unicode\plugins\Config\tidy
to your current Notepad++\plugins\Config folder
Install the xml tools plugin would be a easier way to format xml. Using Pretty print under Plugins -> xml tools