A field is where Email Parser stores pieces of text. There are three type of fields:
Default fields: These are the Subject, Body, From etc. of the received email. These fields are always available.
Parser fields: These are the fields that you define in a Parser. They are always based on the text from an existing field. For example, ‘order number’ is the first word of the second line of ‘Body’.
Fields from Actions: Most actions do not generate any fields but some of them like the field definition action or the HTTP request to an API (among others) can generate fields that can be useful for the next actions in the chain.