The certification screen in Identity Portal only shows the default columns and does not show the columns configured in Identity Governance.
In Identity Governance the initiator of the campaign can select which attributes are viewed by the reviewer.
Identity Portal limits this to 4 attributes in version 14.0, and in version 14.1 this limitation is not present.
You can set the attributes in the display settings in Identity Governance.
The reviewer can click on the settings wheel (on the right side of the headers) and select which attributes to see.