DataTable dt = new
DataTable("Information");
        DataColumn dcID = new
DataColumn("ID",
typeof(int));
       
dcID.AutoIncrement = true;
        dcID.AutoIncrementSeed = 1;
       
dcID.AutoIncrementStep = 1;
        // Add identity column to datatable
       
dt.Columns.Add(dcID);
       
dt.Columns.Add("FirstName");
// Other columns
       
dt.Columns.Add("LastName");
       
dt.Columns.Add("Age");

       
dt.Columns.Add("Gender");

Adding new row in Datatable

dr["FirstName"]
= "Avadhesh";
        dr["LastName"]
= "Patel";
        dr["Age"] = 24;
        dr["Gender"] = "Male";
       
dt.Rows.Add(dr);

The above code will add a new row with the ID = 1.