This field let your insert predefined symbols.
By clicking on the Menu -> Create -> Insert Symbol or by clicking the icon you can design and define on the form template:
width and height by dragging the mouse to the size you want,



A pop-up will appear with the collection of symbols. Click the symbol you want to insert or click ‘Next’ till you find the symbol you want.
To move or resize the symbol see: selecting, moving or resizing fields.
It can be positioned anywhere in the form and once placed it can be moved or resized.