@
It is the symbol above the number 2 on the QWERTY keyboard.
This is the symbol &. It means and.
"au" after an email address, e.g. @mail.au means that the domain where that email address is held originates from Australia. It does not mean, however, that the person who holds the address is necessarily from Australia.
There is no "email" symbol. If you mean the "at" symbol "@" if it is not on your keyboard (on my Swedish keyboard it is <AltGr + 2>) then you will have to find it under Insert>Special symbols. If you mean a symbol of an envelope, then the font "Wingdings" has several *
If they are doing it online, it is because there are computer programs capable of adding email addresses to huge spam mail lists, which can be protected against by writing the email address in an unusual way, such as putting the word at in brackets, or just typing it out, or some other method of making the email address different enough from a normal one that a computer program would not be able to recognize it and start sending spam mail to the person's email address.
it means if you switched your email address!
The term address means the physical location of something. In email, the term address means the name of the email account where you receive emails.
no it means an active email
it means that is your main email that you use for emailing things
You look at the back of the email address.
This means somebody wants an email address where you can be contacted but it is optional, you don't have to supply the email address. This is often found on a registration or application form where your personal details are required.
when someone does " that means there quoting something
That means email address.