What account should be used for asp.net app to save data?

In on asp.net app, I used code below to save data into a file which is located at one file server:

objXmlDoc.Save("\\order\\monthorder\\allorder.xml"))

I got an error message said "permission denied"

How to tell network admin to set write permission for it? What account should be used for asp.net app to save data?

I believe it's either the ASPNET account or the IIS account with write permissions.
I don't have a server in front of me cuz the IIS account is written differently but if i remember correctly the prefix is IIS_something.

The asp.net worker process is part of the IIS_IUSRS group. Give it write & modify permissions on the directory.

Is this shared hosting or an intranet or.....other