In a mail merge, use the Insert Merge Field dialog box when you want to add individual fields from a data source in the main document. For example, suppose that in a batch of letters you want to thank each recipient for his or her financial contribution. Suppose also that the data source that you are using with the mail merge stores this information in a field called GiftAmount. You can use the Insert Merge Field dialog box to place the GiftAmount field anywhere in the document.
If the Match Fields dialog box appears, Microsoft Office Word may have been unable to find some of the information it needs to insert the field. Click the arrow next to (not matched), and then select the field from your data source that corresponds to the field required for the mail merge.
Address fields Click this option to choose from a list of built-in mail merge fields. These fields automatically correspond to the fields in your data source, even if the data source's fields don't have the same name as the built-in fields.
Database fields Click this option to choose from fields that always take data directly from a column in your data file.
Note: If you insert a field from the Database Fields list and then later switch to a data source that doesn't have a column with the same name, Word won't be able to insert that field information into the merged document.
Fields Click the field that you want to place in your document, and then click Insert. When you are finished placing fields in a particular point in your document, click Close.
Match Fields To use all the features of the Word mail merge fields, map the fields in your data file to the mail merge fields that are built into Word. For example, if your data file contains a field called Prefix that stores the values Mr., Miss, Mrs., and Ms., you can map your field to the mail merge field called Courtesy Title. Built-in fields such as Title are automatically included in the composite Address Block and Greeting Line merge fields. Therefore, mapping your data to these built-in fields provides greater automation and flexibility than directly inserting your data file's individual fields in the document.