The Invoice Items card appears when the Custom Charge module is active. Click Add a New Service to add a row, then type the name in the Type to add a service box, set the Quantity with the plus/minus buttons, click the Unit link to choose None, Items, Hours, Days, Weeks or Months, and click the Unit Price value to edit it inline; the Total column updates automatically. The eye icon lets you mark a line as hidden on the customer BEO, and the trash icon removes it. A row is only saved if it has a name and an amount greater than zero.