We would like to add a second email address field, rather than fill in multiple email addresses in the provided email field. I was told there was no way to do this unless I create a new user defined field. We can add new phone fields in the "Phone Type Code" category, which helps us keep all phone data grouped in one area of the persona page. Having the same idea apply to emails could be really helpful!
You can have additional email addresses in phone type codes - this is quite a good workaround