TOPIC:

either intranet has connection to its Company or branch through internet or separated link goes to it destination ???, as extra net has connection through internet to its destination

An intranet is an internal network typically hosting some service people inside the network can use.

So for example a server inside the network could host a webpage only people inside the company could see or a server inside the network could host a ticketing system only people inside the network could use.


An extranet is an external network typically hosting some service people outside the network can use.


So for example a user could log-in to a companies attendance software to clock in from home or log-in to a cloud service somewhere.

In an extranet, external contractor could enjoy the internal services of a company, something like that.