Dayparting is the practice of dividing an online ad campaign to run at different times during the day. For example, you might have a campaign that you have identified works best during work hours, between 10 am and 4 pm, and then after 7 pm until 10.30 pm. Rather than running the ad for the whole day, you turn it off when it is least effective and turn it back on again to run at the optimal time.
While it would obviously be easier to just run the same PPC ads at the same bid for all 24 hours, research done by Service Direct indicates that doing so may be a waste of valuable resources.
You can use dayparting with any PPC ad campaigns, including Google Ads and Facebook Ad campaigns.