Assignments in Canvas is helpful for collecting student work online. Discussions and Quizzes are two related tools that can also be graded. Finally, Assignments drives the construction of the course grade book, so you will need to use it if you plan on using the Canvas grade book.
ITS has an instructional technologist who is available to help you set up assignments and troubleshoot any issues.
Canvas has an excellent video providing an overview of Assignments. For additional information, please see these Canvas articles: