A family of Microsoft spreadsheet software with tools for analyzing, charting, and communicating data.
The best way is to set up all your formulas on the bill to key on a single cell and extract the information needed based on that cell. For example, if you have
Acct# Amount
1234 $43.21
1235 $54.32
....
9999 $98.76
You could use a formula like
=VLOOKUP($A$2,Table!$A:$b,2,False)
to look up the amount. When you change the Acct# entered into cell A2, the value returned by the formula will change.
The specific formulas required to extract the data of interest depends on what level of detail you need to extract - do you need multiple rows of data pulled, or just one, or some other summary?
When you have the formulas all set, you can use a macro to loop through the unique Acct#s, either creating new sheets or printing copies of the bill, depending on what you want to do. You haven't given a lot of detail, so it is hard to proceed from here.