You cannot write to a file via a URL. You can read the file if it was exposed via a URL. To write to a file the host web server would need to expose an endpoint allowing write access (generally via POST) and you'd have to pass the appropriate data.
To talk with OneDrive without using the local filesystem copy you'll have to make REST calls. The API is documented here for reading a file and here for updating a file.
VBScript doesn't support REST directly so you'll have to create and use an instance of Microsoft.XMLHTTP
. Unfortunately the code isn't trivial. Here's a link to some starter code. You'll need to replace the actual logic with the URL and data required as documented in the links given earlier.