Make a beam with light/light visible

If you make for an example, a point light, it will mark a circle with the color that you want, right? It’s a light. But how do i make a beam?? I have been working in a party scene and this is the last detail before finishing it, but i didn’t wanted to use assets, just create a beam myself if possible.

I know that this can be done, but how? Do i need to make a particle? Is there an option that i am missing that allow me to do such thing? Any help would be appreciated =)

What we do is simply create a conical mesh and apply a semi-transparent material with an additive shader.