I'm assuming you mean the padlock on the top of some pages? That doesn't protect the page from being edited, it just shows that the page is protected. Some pages are semi protected because they're high traffic pages and get vandalised frequently. Autoconfirmed users can edit them though. You just need to make many edits and be a user for many days (numbers are not revealed to stop users making pointless edits to get to those numbers) and then you can edit semi protected pages.