The Unicast Address is the Address used in IPv6 for normal point to point communications and there are 3 types of Unicast Addresses
The Global Unicast Address 2000::/3* Public
The Link-Local Address FE80::/10 Private
The Unique-Local Address FD00::/8 Private
They Differ by Their Scope
Global – Scope: Router on the Internet
Unique Local – Scope: Internal to Network, Only Routable inside Private Network
Link Local – Scope: Internal to LAN, Not Routed