An email address consists of:
username + @ + domain name
You can write an email address with CAPITAL LETTERS or with small letters, or with a mixture of the two. For example, JustAnExample@SITE543.COM and justanexample@site543.com are the same.
Email addresses can contain:
- letters of the English alphabet
numbers 0-9
hyphens -
underscore _
dots .
plus of course the mandatory at sign @
For example, all the following would be possible: