When you open openstreetmap.org, on the right-hand side there are some buttons. Click the one that looks like a stack of papers (it’ll say “layers” when you hover it) and there will be an option to enable a notes overlay.
In the editor on the site (called iD) you click the icon on the right that looks like a line and a square (Map Data on hover, or press the U key) and it will have an option to show notes as well.
Generally I leave notes alone for a week or two to see if the user intends to resolve it themself (I talk to myself a lottttt in notes while I’m surveying) but if it’s still there after that, I do my best to resolve it.
That’s the intent of OpenSidewalks, but last I checked it was only available for three cities.