You can set optimization guidelines for your campaigns and ad groups using one of the following optimization types:

• Conversion Funnel. Your campaign and ad groups are optimized based on how you value events in the sales funnel and the relative importance of ad conversions, revenue, clicks, and impressions to your business.
• Business Objective Target. Your campaigns and ad groups are optimized based on a performance goal for your campaign. To define the goal, you need to select a metric (like cost-per-click or cost-per-acquisition) and set its target value.

You can also specify other settings that guide how your campaigns and ad groups are optimized to meet your goals. For example, you can specify ad placement preferences, bidding constraints and more.