Online submission types can be restricted to certain file types.
Click the Assignments link.
Click the assignment title.
Click the Edit button.
Click the Submission Type dropdown menu and choose Online to create the option for students to upload files.
Click the Allow File Uploads checkbox.
Click the Restrict Upload File Types checkbox to restrict file types which can be uploaded. Type the file types you want to restrict in the text field. Remember, all file types need to be separated by a comma. You can include spaces, caps, and periods in assignment file names.
Turnitin Submission Accepted File Formats
Click the Save button.