Italian seasoning is just what it sounds like, a mixture of various herbs like oregano, basil, thyme, marjoram... what you might add to a spaghetti sauce. It used to be my goto seasoning when I felt like spicing up some green beans or other veggie I was sauteing, but then Herbs de Provence came into my life I still keep some Penzeys Italian seasoning on hand though.
I don't know if this would be the same but for years I've made the Eight to Two salad dressing. Eight T. olive oil and 2 T. red wine vinegar. S & P. Almost always add chopped garlic to it but a person doesn't have to.