Shape design and structural design are interpenetrating and cannot be dealt with separately.
In the shape design stage, commonly used software includes:
PS, AI, coreldraw-Draw 2D renderings
Rhinoceros, KEYSHOT, 4D Cinema, Proe…… .............................................................................................................................................................
Proe is now used by more people in modeling design, because it is well combined with later structural design and production. Alias also has it, but not many people use it, and its functions are too powerful, which requires time and energy to learn.
Structural design stage:
Proe and solidworks are the most widely used at present. Catia also has it, but mainly in the automobile industry. UG is widely used in mold design industry, and can be seamlessly connected with PROE and SolidWorks.
There is also Autocad, which may be used at all stages.
There are Macs such as Photoshop and illustrator. Rhino also has it, but Windows is more used in product design, so the software support is better. MAC, all my friends in graphic design are using it. I haven't found the product design yet …
Plastic parts such as mice and pens must be designed for molds. So structural design is inevitable and will be used. You can also ask others to help you. Appearance design must also have a three-dimensional design stage, and now there will basically be more than 2d renderings.
This kind of products, belonging to textiles, need to be opened, cut and stitched, and CAD and AI can be used. But you need to have knowledge of fabric cutting.
I suggest you search the industrial design forum online, and then see what professional designers do, and you will know.