As so many botbr noobs asks where midi files can be created/edited, perhaps a list like this can be useful:

desktop operating systems - exports/imports .mid files:
- '[l[http://ariamaestosa.github.io/ariamaestosa/docs[Aria Maestosa]
- '[l[http://musescore.org/en[musescore] 
- '[l[http://www.rosegardenmusic.com[rosegarden] 
- '[l[https://lmms.io/[lmms] 
- '[l[https://ardour.org/[ardour]
- '[l[https://www.steinberg.net/cubase/[cubase]
- '[l[https://www.image-line.com/[fl studio]
- '[l[https://motu.com/en-us/products/software/dp/[digital performer]
- '[l[https://openmidiproject.osdn.jp/index_en.html[Sekaiju]
- '[l[https://yaru.itch.io/jazz[JAZZ]
- '[l[https://github.com/Hans5958/Domino-English-Translation/releases[Domino (en translated version)]

android:
- '[l[https://play.google.com/store/apps/details?id=com.gamestar.perfectpiano&hl=en&gl=US [perfect piano] (saves midi format, has a virtual piano keyboard, midi/usb controllers can be used)

misc:
- '[l[https://sourceforge.net/projects/munt/files/munt/2.0.0/[munt] uses different instruments, but allows you to capture a midi file from a midi controller connected to your computer
- '[l[https://www.fourmilab.ch/webtools/midicsv/[midicsv] (converts midi to csv and back, command-line based)