I am wondering how to create a 3D online store letting users walk through using a keyboard for example, add their products to their card and finally checkout.
I have no idea which technologies are suitable to use.
Thanks in advance.
BTW apologies for my weak English.
There is no specific technology I know about in order to build a 3D online store. It's something you need to create. Which means your online store will be like any other online store, with only a different presentation layer, hence, a 3D presentation layer
For a 3D space in a web context, you could take a look at WebGL, but it's definitely not the only option. For example, take a look at three.js, a Javascript 3D library, which renders in WebGL, but also in SVG or CSS3D.
If you want something already providing universe creation tools, look at BabylonJS, a Javascript 3D engine, which already provides physics, for example.
You can find many other choices on that page: https://github.com/showcases/javascript-game-engines