Hi Asish, are you exporting the data through the "Extract file"
activity? It has an "Output format" selection on the "File Structure"
tab. Also you should provide a filename including the .csv extension. It
will result in a file eg. "export_20200910_145954.csv" and it will
contain the selected fields separated by comma (CSV = comma separated
values). When you double click such file it is a client side (operating
system level) setting which program automatically opens to read the
file, eg. Excel....