How do we split the XDP File which has both the design and the master Layout into 2 separate templates.
one for the Master and the other for the content.
What is the use case for doing so?
as I understand every xdp needs to have at least one master page
For a better understanding of Masterpages and Fragments you may find some ideas here. It is the SAP LC Designer but the same concepts may help you. Forget about all the SAP related stuff...
Try to understand use of fragments, like @Mayank_Gandhi told, with this Adobe page.
@srinit86581866 save part of the form as a fragment so that they can be reused.
I don't know if I understand well your need. but this small XDP have 2 different master pages, 1 to english part and other for language specific pages.You need some like this, but separated in differents XDP's to reuse it?
Let me know if this is the correct path.