How to set the Hostname? Is there set an email? How can I find it
If this is inside a company network then it's probably a good idea to use the company's SMTP server and put the address or name of the server in there. Any I worked with didn't seem to need a password for mail originating inside the company network.
If you need to use an external SMTP server then get that from the provider's help files or copy it from your email client. This time you will need to provide a login. You don't want to provide your private email and password for this and you might have to create an account just for authentication.