How to create shaders in Unity?

Question

Unity

Hello. I was faced with the need to create a neon glow visual effect in the game. In the internet I found that this can be done using a shader. I also learned that shaders can be written programmatically or combined with different nodes in the Shader Graph Editor. First question: Shader Graph Editor is present only in certain templates, but not in simple 3d and 2d, will shaders made through Shader Graph Editor, for example, work on a phone? If not, how can I make a neon glow effect (or various other effects) so that it works on the phone? If I have to write code for a shader, could you advise me where to start my journey in this topic?