How do you add a recipient to the default public uploadpage?

With an upload request customers can transfer files to you. But how can you make sure they can open the link, a default recipient is added, so they only have to add the files? 

In case the link looks like this: https://portal.smartlockr.eu/uploadportal/phmybt

You can add the following: ?email=info%40smartlockr.eu

The uploadlink will look as followed: https://portal.smartlockr.eu/uploadportal/phmybt?email=info%40smartlockr.eu