You can use midi programs to make midis. Many people use Sekaiju but it's way too complicated for me. I stick to Aria Maestosa. You can hook up a midi keyboard and use it if you have one. You don't need one to use aria maestosa but I'm not sure about sekaiju. Here's the download link for both: https://ariamaestosa.github.io/ariamaestosa/docs/index.html and https://openmidiproject.opal.ne.jp/Sekaiju_en.html