How can I make an indent on a edge loop?

What I'm imagining is essentially like taking an edge loop and pushing it inwards, making an indent. I've tried extruding edge loops down, but that does nothing. I've also tried putting two edge loops on either side of the one I want to indent, and then moving the desired edge loop, but that really messes up the topology. Is there an easier way to do it?

• hello, could you please show a drawing of what you want? – moonboots May 24 '20 at 14:02