Attendance (aka Roll Call) can be added to a Canvas course by navigating to the course and clicking "Settings" in the left-hand course menu.

In the Settings window, click "Navigation."

Scroll down to the area under "Drag items here to hide them from students," click and drag "Attendance" up to the upper section under this sentence: "Drag and drop items to reorder them in the course navigation." You can drag and move course menu items here as you'd like.

Once you have Attendance where you want it, scroll down the page and click "Save." Click "Home" in the course menu to refresh the page/return to your homepage, and you should now see a course menu item for Attendance. Note: Your students cannot see this item in their course menu.

Once you have Attendance added in your course space, this document from the Canvas Community website will walk you through how to use it best: What is the Roll Call Attendance Tool?