Specify in the settings of a regular single item field if you want to set the field value to 0 or 1 depending on whether a certain text is on the invoice.
The system does not look for a value for the field. If it finds the title text, it sets the field value to 1. Otherwise, the field value is set to 0.
The field always has format string N(1).
Defining a field where title occurrence sets the value (Invoice Manager)