Blender

In short: Blender is free 3D software for modelling, animating, rendering and more.

In more detail: The program is open source and developed by the Blender Foundation.

In Depth

Features

Modelling, textures, rigging, animation, simulation, rendering (Cycles, Eevee), video editing. Scripts with Python.

Use

Games (Unity), films, visualisation and 3D printing. For technical designs CAD such as Fusion 360 is more suitable. See TinkerCAD.

See also: Open Source, Unity, 3D Printers, CAD