The Favorites Bar is visible by default, but could have been hidden. To access your bookmarks, you have to pull open the Favorites menu (if you are showing IE's classic menus), or click on the star icon in the top right corner of the window, then find the favorite you want. The favorites bar is ideal for sites you frequently access: depending on the number of bookmarks you add, and how you rename them, you can have quite a few favorite sites only a click away!
First, know that you can show or hide the Favorites bar by right-clicking on the title bar in Internet Explorer 11/10/9 (see screenshot). Check or uncheck the toolbars to toggle them. If you see a checkmark next to Favorites bar, it is already visible; otherwise, click on it to show it. By default, it shows the Bing Suggested Sites, and Bing News Headlines. To remove those, right-click on them and choose "Delete" - that's also how you delete your own shortcuts.
To add any website or web app to the favorites bar, navigate to the exact page you want to see when you click on that shortcut link. Example: to add your webmail inbox (Gmail / Hotmail / Outlook.com / Yahoo Mail / etc.) login and go to your inbox, so that you'll load your inbox next time, not the login screen! Then, click and hold the website icon ("favicon"), and drag it above the favorites bar. When you like the position shown by the vertical line guide, drop it.
To optimize the space, right-click on any shortcut and choose "Rename": now type a shorter name - just enough letters to let you know what that link points to. (Tip: without hiding text labels -see next step- you can shrink its text by renaming the shortcut's title to a single character - that's what I did on the screenshot :) You can rearrange your favorite shortcuts after the fact: just grab one of them, and move it right or left; let go of the mouse once satisfied!
By default, Internet Explorer will use as much space as needed for each link shortcut you add to your favorites bar. That means that you'll quickly run out of space, and have to click the overflow chevron (double down arrows on the right) to see the rest of your sites - not good. Right-click on any link icon or title in your favorite bar, and click on the Customize title widths submenu: you can select to show short titles, or icons only - try both of these to save space!