When we starts to develop our websites, most of the time we need to connect outsider links in our website menu. This tutorial lets you make a WordPress page (or other content type) link to an external URL of your choosing, instead of its WordPress URL.
To do this you just need to follow the simple Steps:
Step 1 : Login To WordPress Admin Panel.
Step 2 : Go To Appearance -> Menus
Step 3 : To your left side there is a section named as Custom Links. Type The Menu Element (Name) and paste the URL which you want to open after clicking the menu element.
Step 4 : Click On Add To Menu.
Step 5: Now To your Right side just replace old menu element with new one and save it.
To Understand It More Properly You can Watch The Video.