I'm linking some of my personal favorite tutorials for these.
For this, it's all about shading and highlighting, and the little rays of light hitting it in the right places so it looks like it is reflecting the shiny surface.
Here are some video titles to videos I find helpful. I couldn't insert links, so I hope the titles will do.
Procreate Tutorial - How to add a metallic 3D effect on the Ipad Pro (Han’made Designs)
Tutorial: How to Draw Metal (Digital)
(sambeawesome)
