Documents in SharePoint Library are not auto-saving

I am running into a problem with making sure documents within libraries are opening SharePoint documents. My Manager uploaded documents into various libraries. I then added columns and updated the properties of the document. Once I update the properties the document no longer opens in an auto-save mode connected to SharePoint but instead opens a copy to save to local drive. How can I prevent this from happening? I would like members of the organization to be able to access the document and work on it with other people on the same document. How can I fix this save function to sync to library?