I need to make a flat file to send data to another organisation.

I am aware of saving Excel sheets as txt files however my problem is
that the other organisation require the @ symbol to be the delimiter
and ASCII 13 carriage return to show the End of Line Marker.

Can anyone give me guidance on how to set the delimiter to be the @
symbol instead of a comma or space?

Using Excel to do this would be ideal as I can make one sheet user
friendly for our users and a hidden sheet linked to user friendly page
to be used to be converted to the flat file (we currently use this
method to transfer data to our bespoke databases).

Any advice or guidance appreciated.

Thanks