Dear Trupthi,
if the barcode can not be seen in the print preview, I assume the "old" barcode printing methodology is used.
SAP Note #1557674 - "Overview of bar code printing from SAP system" lists how barcodes can be printed with SAPScript, and it also shows whether print preview is available for that barcode methodology.
If the "old" barcode printing methodology is used, that means control sequences need to be sent to the printer to activate / deactivate barcode printing. Please check the guide of the barcode module which should describe what is the awaited control sequence for the readable text, as well as if positioning is possible.
If this printing methodology is problematic to use, the "new" barcode technology can be used. The "new" barcode technology allows print preview and some further options.
Please see the previously mentioned Note for details.
Best regards,
Laszlo