Go down the pesticide aisle at your local nursery. There are so many different herbicides to choose from. There's a difference between the different types of herbicides. But herbicides are just one of the ways to manage weeds.
Mowing your lawn at the right height is actually a very effective management technique against weeds. If you mow your grass at the right height, you'll need much less herbicide to manage weeds.
Scalping your lawn? That's mowing too short. Doing this opens up the soil surface to the sun, allowing weed seeds to germinate.