Set up targeting
Ad position targeting
Choose where on webpages you want your creatives to be displayed. Choose Above the fold for the top of the page, or Below the fold for a lower position.
Keep in mind that not all inventory is labeled as above or below the fold. For the strictest settings of including above or below the fold, the line item won't be able to serve for impressions where the ad position is unknown. If you want to place a line item prominently when possible, you could exclude "Below the fold," which prevents the line item from being served to impressions that have been explicitly labeled as below the fold, but still allows it to be served when the position is unknown.