Any recommendation to convert XML to PDF by programming. I mean online free converter can be used to convert XML to PDF but how should i do it via programming. Any leads?

It depends on the XML format you have and your programming skill set, if you know XSLT and XSL-FO or are willing to learn them then you can use software like Saxon 9 and Apache FOP to transform any XML with Saxon to XSL-FO and then that intermediary format with Apache FOP to PDF. For some XML formats like DocBook or DITA there are existing XSLT stylesheets that do the job or can be adapted for a custom job.

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Martin Honnen
Microsoft MVP (XML, Data Platform Development) 2005/04 - 2013/03
My blog

very good info thank you for sharing .

Browse for the XML file by clicking File->Open or pressing Ctrl+O
Click File->Print or press Ctrl+P to open the Printer window
Select novaPDF from the printers list and click Print
Select after saving actions if needed and click OK to convert the XML