Most modern web browsers offer an option to keep your favorite websites open through the entire duration of your browsing session. Until now, the ability to pin browser tabs has been lacking in Safari. However, Apple has recently rectified this situation with the OS X El Capitan update.
The advantage of pinning websites to the tab bar is that pinned web pages cannot be closed unless they are first unpinned. Even if a user closes their browser, pinned tabs will be automatically restored at the next browser restart.
How To Pin Tabs
Pinning browser tabs with the Safari is quite easy. It can be done by simply right-clicking on an open tab and selecting Pin Tab from the contextual menu. You can also pin a browser tab by dragging the window to the left corner of the tab bar (it will shrink in size as you drag it).
How To Unpin Tabs
To unpin a tab, simply drag the tab back to the right, or select the Unpin tab option from the contextual menu.