Can u try the below code in invoke code activity with langauge type as c# dt1.AsEnumerable().ToList.ForEach(x =>{
x(“Category”)= “Foods”;
x(“Product”)= “Goods”;
});
where dt1 is the datatable variable passed as an argument In/Out to the invoke code
there are multiple ways you can achieve this without using loops
using invoke code activity:
dt.Columns.Add(“Column3”,GetType(String), “value”) <<< this creates a new column
or
dt.Columns.Item(“ColumnName”).Expression =“‘value’” <<< this sets values of an existing column
using Excel (if you have cell range handy or calculated)