iService forms use commands, the iService Scripting Language, to interact directly with the iService system. These commands are automatically converted into the necessary HTML code for the form. There are two types of commands: those used within the Form Body and those used within submit Actions.
Similar to other commands and variables within iService, form commands are enclosed within a $. For a full list of all available commands , see https://1to1service.iservicecrm.com/f/diag-regex. Many of the more common commands are listed within the forms variable picker in the Admin Tools-Forms page. The forms variable picker will paste the proper syntax into your form for each available property in your tenant.