You can show the sum of a selected set of cells by setting the summary bar to Sum, selecting the group of cells, and looking at the summary bar. Here’s a gif showing how to do that:

that is just for one column but I can’t get the total sum of two columns?

@Ali_Aboutera You may consider summing two cells in a 3rd cell by formula. When you sum the 3rd column as shown above, you should see the totals you are looking for.