By default, when you create a new course, your students can request manual extensions, but not automatic extensions. When you copy a WebAssign section, the extension settings are copied over to the new course or section.
Extensions
You can grant extensions to give your students more time to complete their work in WebAssign. You also have the option to set up automatic extensions or disallow extension requests for specific classes or assignment categories.
GuideInstructor HelpWebAssign