So, you want it to display
Invoice Number:
followed by the invoice number? Simple!
Where it says
echo "%variable%" > some_file
replace that with
echo Invoice No: "%variable%" > some_file
If you want it to display Invoice No at the begining, that gets a bit tricky...But it's still possible!
Echo Invoice No: "%variable%" > some_other_file
type data.txt >> some_other_file
type some_other_file > data.txt
del some_other_file
There, that will do it. Here is a step-by-step explanation of the script:
1. Sends "Invoice No: %variable%" to some_other_file which is important.
2. Sends the full contents of data.txt to the end of some_other_file.
3. Sends the full contents of some_other_file (part 1 + 2) to data.txt and overrides anything that was previously in data.txt
4. Deletes some_other_file.
Understand?