OneBox OS allows you to create your own interface fields. For example, if the standard fields are not enough for you, then you can create your own and add it to the contact card interface.
To create an additional field for a contact, you must:
Open the "Contacts" application:
Select "Additional contact fields":
Click the Add Field button:
Specify the name of the field and its type:
Click “Insert New Record”:
An additional field has been created, now you need to display it in the contact interface, for this:
Go to the interface settings of the contact group where you want to display the created field. Select a universal block in which this additional field will be displayed:
Check the created additional field and save the settings:
After that, this additional field will be added to the contact: