Where is the datasource?  If you were using Word to create it, you could use
it as the data source for a Catalog or Directory type mailmerge in the main
document of which you insert a one row table into the cells of which you
insert the individual merge fields.  When you execute that merge to a new
document, that document will contain a table with a row of data for each
record in the data source.  You can then add new columns to that table and
insert a row at the top into the cells of which you enter the names of the
merge fields.  That document can then be used as your data source.