As you are likely aware, ads placed through the Denim platform have the ability to be placed in multiple areas within our supported social networks. These different options are called placements.
Check out this article for more information on the different placement options supported by the Denim platform.
The difference between automatic placement and manual placement is simply who's deciding where to place the ad: Denim (automatic placement) or you (manual placement).
In automatic placement, the Denim platform will pick the best placements for your ads based on the budget you've set for your campaign to optimize for your goal (awareness, engagement, or conversion). This will span across both Facebook and Instagram.
In manual placement, you will be able to select the exact placement options you desire.