Open the Terminal and tun the following command :
sudo apt install openconnect network-manager-openconnect network-manager-openconnect-gnome
After you installed, go to 'Setting' then 'Network'
Click on '+' to add VPN then select 'Cisco AnyConnect Compatible VPN'
Put name as 'FREEVPN724' and in Gateway field 'https://us1.freevpn724.com' and then click on 'Add' button
Click on created VPN profile to go online.
It maybe alert you about Certificate, Click on 'ok' and follow.
Put the VPN Username.
Put the VPN Password.
Now you connected to VPN.
Enjoy Free VPN Services.