Anyone can make edits in OpenStreetMap (OSM), all it takes is a free account. After you create your account, there is even a tutorial (see below) that teaches the basics of OSM editing, as well as a “Beginner’s Guide”
Also, at the bottom of the OSM Welcome Page is this:
No Time To Edit? Add a Note!
If you just want something small fixed and don’t have the time to sign up and learn how to edit, it’s easy to add a note.
Just go to the map and click the note icon 
This will add a marker to the map, which you can move by dragging. Add your message, then click save, and other mappers will investigate.
OSM Tutorial
The option to take the tutorial showed up by itself after I registered. If you don’t get the option, or want to take it again, see this page: Interactive tutorial to getting started editing OSM - OSM Help
Pressing H (Help) works too, to access the tutorial option (on help screen)!
There is also this Wiki entry on editing: OSM Basics . It “summarizes a few techniques for fixing common OpenStreetMap (OSM) errors that found their way into CityStrides.”