How to keep a space character at the end of a value (for barcodes)

Hi,
i loaded my .xls inventory file into excel to edit it and it auto removed all the spaces at the end of my barcode numbers.
I don't know why my inventory program uses spaces at the end of the barcode number but apparently it does
I'm trying to add the spaces back into the value, but as soon as hit the enter button it disappears again.

any suggestions to this? thanks