Domestic or longarm quilting?
Domestic, there's sometimes a plastic foot for the free motion/hopping foot that looks like a target (concentric red circles on a clear circular foot).
Longarm - some manufacturers sell echo feet of different diameters - same idea, you use lines on the foot to try and guide around applique or echo previous stiching.
You don't mark the quilt - you use the edge of the applique as a visual guide for the foot as you quilt.