New Column

[dhruvi-alphabin]

How can I add new column?

[theoephraim]

if you mean inserting more columns into the sheet, https://theoephraim.github.io/node-google-spreadsheet/#/classes/google-spreadsheet-worksheet?id=fn-insertdimension

If you mean adding a new header for the row-based api, you can use https://theoephraim.github.io/node-google-spreadsheet/#/classes/google-spreadsheet-worksheet?id=fn-setheaderrow