The Census Data export contains just the editable data fields. You can export the Census Data to add/edit employees, then re-upload it into Kamsa (to apply the employee data edits).
The Employee Data export includes all data within the Employee Data page in Kamsa.
If you have a filter applied within the Employee Data page, then the export will include only the employees that fit the filter at the time of export.
Video: How to export Employee Data
Video: How to edit Employee Data