Do you have a points or percentage based gradebook? If it's a percentage based gradebook then you could create an extra credit assignment group and add the roll call attendance assignment there - Extra credit using weighted assignment groups.
I have no idea why this question is posted under my name. I teach online at this point, and attendance is not an issue. When I teach live classes, I use PAPER to have students sign in. I don't like CANVAS, and I use it as little as possible. I did not ask this question. I don't know who did or why it is listed under my name. It's just one more problem with CANVAS that takes up time I could be devoting to working with my students and TEACHING my classes. Technology that changes frequently and is too complex ceases to be a tool and becomes an obstacle, which is exactly how I view CANVAS.