Writing to a directory on a webserver

What permission must a folder have in order to write to it and delete a file and read a file from that folder. And what account must have those permissions on that folder is for an asp.net app to write a file to that folder allow the user to download it and afterwards delete it. I have set this up on the computer I test my apps on however that was a trial an error thing and Im not exactlly sure what I did to get it to work. Now I need an explanation of how to do this since my app is moving to a non development server. Any help would be greatful.

There is an ASP_NET user that needs to have permission to read and write.

Aside from that, it's fairly straight-forward.

Does this make sense I only have the asp_user with read access and special but I have the creater owner group set to full control would that by default give the asp_user control over its own file it creates?