This sample demonstrates how to update the fields available in the Word document using Essential DocIO. Here, in the example, merge fields and formula fields are used together to populate the net profit or loss.
Fields in a Word document are like placeholders where the data can be populated or calculated dynamically based on various factors. Most control-sectionly used fields are merge fields, Table of contents (TOC), page number related fields, IF fields, date fields etc.
Another example: IF field compares two values and then inserts the text appropriate to the rest of the comparison. When used in a mail merge, the field can examine information in the merged data records, and populate appropriate text.
More information about the fields and updating fields can be found in this