Specifically, when an instructor uploads and attaches a file, such as a pdf when editing a page, the pdf does not include the "Preview" option automatically. Instead, the file is left with only the "Download" and "Alternative Formats" options. The workaround is for the instructor to delete the link that was created and to select the pdf from a list of files to recreate the link to give it that "Preview" option.
Steps to reproduce:
1. Edit a page in a Canvas course.
2. In the menu on the right, click on the "Files" tab.
3. At the bottom of the menu, click on "+ Upload a new file".
4. Click the "Choose File" button and select a pdf.
5. Choose any folder and then click "Upload".
The file link is added to the page and includes a "Preview" option if it is a readable format.
The file link is added to the page and does not include a "Preview" option, but only a "Download" and "Alternative formats" option.
The "Upload a new file" feature included when editing a page is very convenient for instructors, so it would be nice if it included the "Preview" option so as to not require extra unnecessary steps from instructors to let students preview them. This would also make the file uploading process more consistent across Canvas as .pdf and .doc files are expected to have the option to "Preview" when linked in Canvas.