Number one, I would like to say that I hope I found the right forum, becuase I’m not entirely sure where to put this. Lately I have been working on a scene that involves a cup of coffee. To make it more realistic, I would like to have foam on the top. How would I achieve this? Thank you to any answers in advance.

That could be difficult… but maybe not impossible, hard as hell to render if you do it with bubbles, you might be able to do some sort of instance with a sphere

For a fine form, you can get away with using just bump texture straight out of Blender Voronoi texture. Here is my quick foam straight out of Voronoi: