The following config will discuss an installation of Skype on Ubuntu 16.04 Xenial Xerus 64-bit Linux.

Install from Ubuntu Partner Repository

Below commands will install Skype from Ubuntu's partner repository:
$ sudo add-apt-repository "deb $(lsb_release -sc) partner"
$ sudo dpkg --add-architecture i386
$ sudo apt-get update
$ sudo apt-get install skype
Skype should now be installed on you Ubuntu 16.04 system. Use Ubuntu's application menu to start Skype or start Skype directly from your terminal:
$ skype

Manual install

Start manual Skype installation by downloading the latest official skype ubuntu package from website.

Alternatively use the wget command below to download Skype Ubuntu package directly from command line. Please not current version of skype may be different:
$ wget
Since we are trying to perform an installation of i386 package on 64-bit system we need to enable multi-architecture to support both platforms:
$ sudo dpkg --add-architecture i386
$ sudo apt-get update
At this stage we use dpkg command to install the previously downloaded Skype package:
$ sudo dpkg -i skype-ubuntu-precise_4.3.0.37-1_i386.deb
Unpacking skype:i386 ( ...
dpkg: dependency problems prevent configuration of skype:i386:
 skype:i386 depends on libc6 (>= 2.3.6-6~).
 skype:i386 depends on libc6 (>= 2.7).
 skype:i386 depends on libgcc1 (>= 1:4.1.1).
 skype:i386 depends on libqt4-dbus (>= 4:4.5.3).
 skype:i386 depends on libqt4-network (>= 4:4.8.0).
 skype:i386 depends on libqt4-xml (>= 4:4.5.3).
 skype:i386 depends on libqtcore4 (>= 4:4.7.0~beta1).
 skype:i386 depends on libqtgui4 (>= 4:4.8.0).
 skype:i386 depends on libqtwebkit4 (>= 2.2~2011week36).
 skype:i386 depends on libstdc++6 (>= 4.2.1).
 skype:i386 depends on libx11-6.
 skype:i386 depends on libxext6.
 skype:i386 depends on libxss1.
 skype:i386 depends on libxv1.
 skype:i386 depends on libssl1.0.0.
 skype:i386 depends on libpulse0.
 skype:i386 depends on libasound2-plugins.

dpkg: error processing package skype:i386 (--install):
 dependency problems - leaving unconfigured
Processing triggers for hicolor-icon-theme (0.15-0ubuntu1) ...
Processing triggers for gnome-menus (3.13.3-6ubuntu2) ...
Processing triggers for desktop-file-utils (0.22-1ubuntu3) ...
Processing triggers for bamfdaemon (0.5.2~bzr0+16.04.20151217-0ubuntu1) ...
Rebuilding /usr/share/applications/bamf-2.index...
Processing triggers for mime-support (3.59ubuntu1) ...
Processing triggers for dbus (1.10.6-1ubuntu1) ...
Errors were encountered while processing:
To fix the above dependencies problems run the bellow command which will install all required dependencies as well us the actual skype package:
# apt-get -f install
Setting up skype:i386 ( ...
Setting up qt-at-spi:i386 (0.4.0-3) ...
Skype is now installed and ready to use. If you cannot find skype shortcut on any of the GUI menus re-login or simply start skype from terminal by typing skype command:
$ skype
How to install Skype on Ubuntu 16.04 Xenial Xerus Linux 64-bit