I do not think skype needs any explanation.
How to install it on ArcoLinux?
sudo pacman -S skypeforlinux-stable-bin
It is interesting to know that you can create an account on skype with a gmail account.
Then you need to get into contact with your friends and ask them their skype name so you can connect and meet with each other. You can share your desktop if you want to explain/teach something to them.
Playlist on Youtube : Communication Applications