Also, you can select hoc http requests as "Data source". This is a universal method to accept ad hoc requests from services.
Depending on the chosen source, you will access a list of fields that will be processed.
For example, if you select Facebook lead forms as a source, you will have access at least to the following fields:
Lead ID, Creation date and time, Ad ID, Ad name, Ad group ID, Ad group name, campaign ID, campaign name, form ID, Form name, page ID, Page name, Full name, Phone number.