How do you implement 3D models in WEB?

https://doc.babylonjs.com

Yes, and in fact Google knows many options: pow

Hello!
As already written, it is necessary to use WebGL. But to use it you can:
- up framework (Three.JS/BabylonJS)
to study three-dimensional graphics and writing shaders from scratch (clean WebGL)
- use of three-dimensional CSS (not necessary!!!)

It is important to consider a huge number of points, including: coordinates, rendering, etc.
It's not easy :)