What is your best [female] friend's e-mail.
they are asking. What is your friends email address?
Mi correo electronico es... abcdby@mail.com
Which is you're best friends email address?
cual es tu correo electronico = what is your email-address You could simply give your email-address, or preface it with: 'Mi correo electronico es....' = 'My email-address is....'
What is your email.
it means what is your email address
Cual es su correo electronico?- formal way me pasas tu email? -informal way
They are asking for your email address, you can answer by either giving it to them of refusing to do so.
Translation: What is your best friend's e-mail.
Wilson :v
What is your email.
que es el mejor or cual es