I am learning ShaderLab for a while but I found most tutorials use ShaderGraph,so I wonder in work which is more common ? Which tool should I use? 
Shadergraph is node based. It’s also a little easier to take those skills into ue4’s material editor or other editors in unity like amplify. it’s a great way to start learning shaders. A lot easier/more artist friendly than writing them so I’d recommend it.
In work it really depends. I’ve found myself in charge of shaders i’ve needed for vfx and used amplify for it. i’ve also had times where someone else was in charge of writing shaders but I could get everything set up pretty well in amplify and have them review it.
Thanks for your answer:-) Do you think learn something about rendering or direct3D (OpenGL) is good to make VFXs?
I havent lerant it ,but plan to do .