https://developer.servicenow.com/dev.do#!/learn/courses/sandiego/app_store_learnv2_learnmore_sandiego_learn_more/app_store_learnv2_learnmore_sandiego_form_and_list_layouts/app_store_learnv2_learnmore_sandiego_what_is_form_designer

The Form Designer is a tool that allows you to create and customize forms on the ServiceNow platform. The Form Designer has four main components:

Form layout: The form layout shows the preview of the form and allows you to drag and drop fields, sections, and related lists onto the form. You can also resize, reorder, and delete the elements on the form layout.

Page header: The page header shows the name of the table and the form that you are editing. You can also access the form properties, save the form, and switch to the form view from the page header.

Field navigator: The field navigator shows the list of available fields for the table and allows you to search, filter, and add fields to the form. You can also create new fields and edit existing fields from the field navigator.

Schema map: The schema map is not part of the Form Designer. The schema map is a separate tool that shows the relationships between tables and fields on the platform. You can access the schema map from the System Definition > Tables module or from the context menu of a table.