This field provides a location for you to store additional Supplier contact information (e.g. Sales Manager, General Manager).
To populate this field, drag and drop existing Contact Records from the Contacts Menu to the Additional > Contacts table, then create a new Contact Record by clicking the Yellow Plus in the top right corner of this tab.

To create different Content Categories, go to Tools > Setup > General Lists > Lists > Contact categories and in the adjacent List Values field click the Yellow Plus to add a Contact Category.

This facility is useful to identify the Contact type (for example supplier contacts, agent clients, client contacts etc.). You can then tick this Contact Category under the Additional Tab of the newly created Contact Card.