or simply production of publicity materials, as advertising is covered in the meaning of "publicity"

I agreed with the answer above but didn't like "advertisement materials"

just another way of phrasing it...

Just thought I might throw my hat in the ring...This is pretty much literal, but I'd suggest putting "promotional" in to distinguish it from other possible types of advertisements (say, public service messages, etc.).

I'd tend to choose production over creation here, as there's a flavour to it of making something for a specific purpose where the maker brings together all sorts of facets of the work to create a shiny finished product. Anyways, that's just being semantic...

Hope I've helped, & have a nice day