Create a custom field

Create a custom field for your account. The label field must be unique to your account. Whitespace will be removed from the beginning and the end of your label.

Additionally, a key field and a name field will be generated for you. The key is an ASCII-only, lowercased, underscored representation of your label. This key must be unique to your account. Keys are used in personalization tags in sequences and broadcasts. Names are unique identifiers for use in the HTML of custom forms. They are made up of a combination of ID and the key of the custom field prefixed with “ck_field”.