UV Outliner is, as the name suggests, a program for creating outlines on your PC. Use it to keep track of notes, ideas, expenses, tasks and so on. You can easily move items around, and promote or demote them in the hierarchy.
The program is a 2 MB download from http://www.uvoutliner.com/ and it's free. It's also malware-free according to VirusTotal.
Although UV Outliner hasn't been updated since 2012, it works just fine on Windows 10. Plus, it saves its files in XML format so if you need to maintain or edit them outside of UV Outliner it's easy.