Blender is a 3D modeling software that allows users to create and edit their own models. Users can create models by sculpting, modeling, texture painting, and animating using various tools and techniques. Blender is widely used in the gaming and animation industries, and its open-source nature allows for a large community of users to share tips, tricks, and tutorials. These models can be exported in 3D printing formats to be sliced and produced on the 3D printers.
The image below is an example of how 3D objects are painted (called a texture) in Blender.