I know this post is quite old, but I was helping a student with this issue today and wanted to share my knowledge. Usually, if the student cannot find the file on their Mac, it is because the file is saved on OneDrive, and the student doesn't have a link to their OneDrive in Finder.
The easiest option is for the student to open the file, click save as, and then save it to a location on their computer. I typically recommend either the desktop or the documents folder since they are easiest to locate, but as long as the student knows how to find that file location, anywhere on the computer will work. Once the file is saved on the computer, the student can submit it by following the instructions in this article, https://community.canvaslms.com/t5/Student-Guide/How-do-I-upload-a-file-as-an-assignment-submission-....
Alternatively, if the student would like to save themselves the step of saving files directly to their computer, they can add a link to OneDrive directly on their computer. There are instructions on syncing OneDrive to Mac at this link, https://support.microsoft.com/en-us/office/sync-files-with-onedrive-on-mac-os-x-d11b9f29-00bb-4172-b....
Hopefully, people will find this helpful.
This discussion post is outdated and has been archived. Please use the Community question forums and official documentation for the most current and accurate information.