Plug In for File Upload from Customers

I have a client who is a printer. He wants his customers to be able to upload their printing jobs to his FTP server through his website. He will then access the files to print them.

I am having trouble stating what I’m looking for in terms that the search engines brings up a list of plugin options. Do you know of a plug-in that will provide the utility we need?

Thanks in advance for your advice.