Message settings - can't add phone number only emails?.

[Saree18]

First post, so please be gentle!,

Got my new iPhone and my hubby is away and texing me. These are coming through as emails to my icloud account. Apparently I have to go into settings and change the email 'receive at' to my mobile number but this isn't an option?.

It will only let me add other email addresses?..

Please help Sarah