If you want to insert an ITF-14 barcode in a template, then you need to insert a barcode element, where you select it as the barcode type:
The parameters are:
(The headers are links to the common description).
Data
The data, that you want to put into the barcode.
Preview placeholder
Here you can enter a text constant for the data, that you want to use for the barcode in the result view in the designer.
Height
The height of the barcode.
Error handling
How InterFormNG2 should react, if the data used cannot be converted into the barcode e.g. because of unsupported characters.