Really, it depends on which mail service you are using. Mostly, however, you click "New" or "Compose", then type in their email where it says "To:" or "Receptaints email". then in the big box or the...
There is no correlation between the two. A server can have an IP address without having any form of email system on it, and a server with an email system can have more than one account, and more than...
You can actually find the physical location of the system which has been used to send an email. You can do this by analysing the header of an email. Normally the header of email will contain the...