Click on the Contacts tab. Click on the icon located on the right side of the screen (as shown below). A new page titled "Column Selection" will appear (as shown below). To reset the column selection, click on the Reset button.
Click on the Prospects module. Click on the Column Selection icon (as shown below). Check or Uncheck the box to view custom columns. Click on the Apply Changes button to take effect or click on the Reset button to revert to the default selections.