A description of the definition for each KPI can be seen in the application on the VBD's KPI landing page. You can get to this within the Marketing portal by clicking the "Configuration icon" (in the portal header on top right) and selecting the menu option "Visual Business Director". The "Key Performance Indicator" landing page is on the second tab.
Note : You can also access this landing page in "Designer Studio" via the menus Configure->Decisioning->Monitoring->Visual Business Director-> Key Performance Indicators
As well as seeing a description of each KPI, you can click on the name of the KPI to see a more detailed view of its definition.
The "Outcomes" these KPI's are based on i.e. "Pending", "Accepted", "Impression", "Clicked" etc are set depending on how you are using Pega Marketing. These outcomes will be recorded if you are using Campaign, Action processing or viewing an email treatment and are based on a customer getting an action/ offer.
i.e. If you create a multichannel campaign that sends out a single offer to a single customer, a "Pending" record will be written to IH & VBD and the "Total Sent" KPI will increase by 1. If your offer flow sends out an email, when that email is viewed, an "Impression" outcome will be written to IH & VBD. Now if your offer flow is written in a way that an Update Status shape is triggered that has been configured as a positive "Accepted" response, this outcome will be updated and the "Total Accepts" KPI will increase.
Note : There are 4 KPI's shipped by Pega platform and not Pega Marketing "Volume", "Accept rate", "Total accepted", "Total rejected". These KPI's do not look at outcomes recorded by Pega Marketing.
I could confirm the definition for each KPI, but I had another question.
As for your Note that "There are 4 KPI's shipped by Pega platform and not Pega Marketing "Volume", "Accept rate", "Total accepted", "Total rejected". These KPI's do not look at outcomes recorded by Pega Marketing"
How could you look at outcomes in Pega Marketing? Do I need to configure the case type in Pega Platform, and then connect the KPI?
And you mean that Do I need to buy license in Pega Platform?
If you notice the definition of the platform KPI's check for an outcome of "Accept" or "Reject". However Pega Marketing records the outcomes as "Accepted" or "Rejected" plus many others. As you are have Pega Marketing, you will probably not want to use the platform KPI's ie instead of using "Volume" use "Total Responses" etc. Alternatively you can update the definition of these KPI's to also include the Pega Marketing outcomes, so the defintiion for "Volume" becomes the count of "Accept", "Reject" &"Accepted","Rejected"