AutoCAD is an old and long-established CAD application, and probably has the most existing drawing files of any. It’s very flexible and used in lots of different ways, not just mechanical design.

Catia is CAD tool and can be used for different design stages. You can draw your concepts on it, modify them, simulate them, identify problems and finally detail them to go the production.

Capabilities of designing parts, sheet metals, surfaces etc. along with the ability to assemble the parts and produce engineering drawings using the 3D model that's designed.

It's considered a mainstream mechanical engineering tool. It's used in enough places that It's frequently exchanged between companies for manufacturing quoting, conceptual development and analysis.