I was wondering if it would be possible to create a custom post with different custom fields so that if a download document used in many pages changes the user can come here to update the name.
In other words, if the document sitting in www.web.com/uploads/catalog2012.pdf is upgraded to catalog2013.pdf, the user would be able to change the document name here.
Thanks in Advance,
Post meta data are for posts only. You should not create a new post type to use custom options.
There is a dedicated Options API for that use case. Create an options page and let the user update the option there.