There are multiple assignment types that can be used in Canvas.

Regular Canvas assignments, course Group assignments, Peer Review, Turnitin (full Turnitin and Plagiarism Framework), and VoiceThread

Note - grade center categories are also called groups in canvas, so if you're looking to create a Group Assignment you need to look for "Course Group" not assignment group.

Please see the links below for more information on creation, grading, etc. of assignments:


Turnitin assignments

VoiceThread assignments