is there any way to download document file from Process Model by initiating the process

Hello Ahmad, we can create a document by starting the process model but we need an interface to provide the document download link and download the document but there is no direct way to download the document. 

What are you trying to achieve here? Users will not be able to initiate a process directly- without interacting with a UI that has option to initiate a process. If the user wants to download a document you can directly use a document download link field in that same UI to enable user to download the file.