Your comment would be relevant if, by installing the OneDrive for Android application on a device, it gave you an extra option to open a file from OneDrive. It doesn't. You CAN open files (and so edit and save back) directly from Dropbox, Google Drive and Adobe's own cloud storage offerings. This is what the user was looking for but for OneDrive, or a similar workaround. I know because I have been looking for the same workaround and ended up moving my files (back) to Google Drive to have this.