Choose newline character in Notepad++

For any new document: Settings -> Preferences -> New Document (left pane) -> New Document (right pane) -> Format (Line ending) -> Windows (CR LF) / Unix (LF) / Macintosh (CR)

And for an already-open document: Edit -> EOL Conversion

on windows 10, Notepad 7.8.5, i found this solution to convert from CRLF to LF.
Edit > Format end of line
and choose either Windows(CR+LF) or Unix(LF)

"Edit -> EOL Conversion". You can convert to Windows/Linux/Mac EOL there. The current format is displayed in the status bar.