Free and open source music notation program. From website:
MuseScore runs on Windows, MacOS, and Linux, and is available in over 40 different languages.
- Create sheet music with WYSIWYG editor
- Listen to your score with computer playback
- Share & print your score
- Work the way you like
- Get help
MuseScore can import and export MIDI and MusicXML files, and it can also import from Capella and several other programs. MuseScore can export to PDF, PNG, and other graphic formats, to WAV and other audio formats, or to LilyPond for an alternative layout and print option.
MuseScore can upload scores directly to the score sharing site musescore.com. Program support is provided on musescore.org.