By default, all new line items will target both desktop and app inventory. If you want to target only specific types of inventory, you can use the following types of targeting.

• Position targeting

  Use position targeting to control where your ads appear relative to other content, whether it's text on a webpage or within a video stream. 

• Environment targeting

  Use environment targeting to target based on web versus app serving environments. You can also specify if you want to target inventory not optimized by device type, such as sites that are defined for desktop but viewed on mobile devices. 
• Device targeting

  Use device targeting to target people based on the hardware they're using:

  • Device Type (e.g. "Tablet")
  • Device Make (e.g. "Samsung (All Models)")
  • Device Model (e.g. "Google Nexus 4")

  You can also use device targeting to target people based on the operating system they're using.

• Carrier/ISP targeting

  Use carrier/ISP targeting to target people based on their mobile carrier or ISP.

• Browser targeting

  Use browser targeting to target people based on their mobile browser.

• App targeting

  Use channel, URL, and app targeting to target impressions associated with specific mobile apps.