A Blackboard Assignment is an online submission point for your assessment. You can grade student work (offline or online) and provide feedback in a variety of ways using inline comments, a designated feedback box, or by uploading files.
Using a Blackboard Assignment gives you flexibility. It allows for students to submit multiple files at once, supports a wider variety of file types than Turnitin, and supports files larger than 40MB. However it does not provide the Turnitin originality report.