You can read an overview of parameters here.
The Identity parameter filters contacts based on personal information provided by the contact. Below are the parameters you can use to target contacts.
You can use these by themselves or combine with other parameters to narrow your segment further.
Contact type - Shows whether the contact is a subscriber, customer or guest customer. This field is set by your store platform.
Basic info - First and last name, email address, phone numbers.
Geographics - Address, region, country and postal code.
Demographics (PRO) - Gender, age, nationality, language.