I have Notepad++ and I got some XML code which is very long. When I pasted it in Notepad++ there was a long line of code (difficult to read and work with).
I want to
"But can Notepad++ do it?"
If the XML is invalid, the answer is apparently 'no'. I tried Notepad++ with the Tidy2 and XMLTools plugins. Both give errors similar to "errors encountered, please fix". If you don't care about errors, that's a PITA.
Instead, open it in visual studio then edit -> advanced -> format document. Quick and pretty.
Try TextFX → TextFX Html Tidy → Tidy: reindent XML
If you can't try with Eclipse, do right button, source, and correct indent.