You can't send parcels. When you use e-mail you need to address the message to the person you want to receive it, just as you do with conventional mail. The person is not the real name of the person, instead it is an alias chosen by them, or assigned to them by their Internet Service Provider. There may well be another John Smith who uses Dial, and he might be using that alias.
Attachments are the e-mail equivalent of parcels.
The bigger the attachment the longer it will take to send and receive the message, so if you are sending a very large file it may be an idea to break it into a number of smaller attachments. The person receiving the attachment will need to have appropriate software to view the attachment on their computer. For example, if you are sending a bitmap file they will need a graphics package capable of viewing bitmap files. Mailing lists are set up so people with similar interests can discuss the subject they are interested in. Once you have sent e-mail it is first transferred to the server on which you have your mail account, and is then sent to the server on which the recipient has their mail account.