When you first login to SharePoint, on the default layout, you have two navigations bars. The Top Link Navigation (which we will cover in a different article), and the Quick Launch bar located on the left of the screen. At times, you may want to remove, or add, new links to this navigation. This is really easy to do and this guide will help you accomplish this.
After you click Edit Links, you will see you now have some editing features. Click the "x" on any link you would like to remove.This will remove the link to the list/library/site only. This will not actually delete the list/library/site, it only removes it from the quick launch.
On the pop up window, type out the display name that will show up in the quick launch, and then the URL it should go to. Once you are finished, you can click OK.
You will now see your new heading in the quick launch bar. Next, click Save. Now go and click your link and it should direct you to the page you linked. You can also link different parts of your SharePoint site and other Site Collections.
Now there is another way to do this.
Login to your SharePoint site and click the jog wheel on the top right next to your name and go down to Site Settings