This is not related to Open XML SDK, so off topic in this forum.
We cannot provide an answer or any suggestions on this since the requirment is not clear. How do you want to convert the XML file to pdf? XML is data container while PDF shows the data in some structures.
Best regards,
Ji Zhou - MSFT
Microsoft Online Community Support
Please remember to mark the replies as answers if they help and unmark them if they provide no help.