Orders contain Line Items (for ads), each of which provides information about individual campaigns that make up an Order.
Example: A company creates advertising line items for each geographic region or for a time-specific duration (e.g., weeks prior to a major holiday or seasonal event or line items for ski equipment in geographic areas with snow, adventurous people, and mountains).
Each line item has a budget cap for financing, e.g., 1000 impressions per day or a total of 10000 impressions. Line items can target particular market segments by specifying demographics and managing the time frames, geographic locations, and display devices for impressions.
You cannot create a PMP Line Item from the Ad Server; it must be created in the PubMatic SSP account. All PMP Line Items created, however, will appear in the list of Line Items on the Ad Server.
Learn more about Line Items: