It is COST PER ACTION
It’s the cost spending on clicks / conversion .
Example : Let’s say your ad drew 100 clicks at 100$, and you achieved 10 Conversions, then you CPA is 10$.
The lower the CPA value , means good is the conversion rate.
It’s the most important for the user to take any action.Call for Action is what drives the users to interact with your campaign. Depending on the goals that the advertiser set for the campaign, the Call for Action may be: Request a quote, download a brochure, sign up for a newsletter, and of course- buy a product or book a room online.