Drawing Software
If you want free drawing software or image editing software, there are:
- Inkscape → line drawing
- Gimp → image editing
- paint.net → a very simple paint program.
- Krita → paint
- MediBang Paint
- Autodesk Sketchbook
They are available for Mac, Windows, linux.
For 3d, see List of 3D Modeling Software
best drawing app is krita. don't use gimp
MediBang Paint

Autodesk Sketchbook
