Krita is a fully-featured open-source digital art app for Windows, Mac, and Android, if you want to paint and draw.
Gimp is the best free digital art software on WIndows, Mac, and Linux. The open-source drawing app is as powerful as Adobe Photoshop, however, there is a learning curve to mastering the tool. The freemium Adobe Fresco is also worth trying, without having to pay for the full app. Krita is a fully-featured open-source digital art app for Windows, Mac, and Android, if you want to paint and draw.