This should be given to you by your ISP. It also depends on what email client (Outlook, Outlook Express, Thunderbird) that the client is running. You will need to provide more details about what you are looking for.
Your SMTP server is your email provider’s server. It does not belong to “any p,c,”, it belongs to the email provider you use. If you use comcast for instance, the smtp server address is going to be the same, smtp.comcast.net, no matter what p.c. you use. If you do not use comcast, then that smtp server address will not work for you no matter what p.c. you are using. So find out what your email provider’s smtp server address is.