We are a small property maintenance company. We don't have an invoicing system, as every job is different, so it isn't possible to build templates. Instead, the person who does the job writes everything down, numbering each job for clarity.
The workflow
I attach that document to a project in Claude, along with a couple of template items: a list of customers and an invoice template document. Claude then builds all the invoices, calculating VAT on the net rate, and the totals.
The result
I used to spend about an hour setting each document up, depending on how many there were: adding the customer name and invoice number and formatting the page or pages. Then I'd run through the main info document, change everything into past tense and add VAT and totals, which took around 2 hours. Then copying everything into the set-up document took around 1 more hour. I could usually lose 5 hours doing the invoices.
Time saved is about 4 hours. I still do a final manual check to make sure the invoice numbers, text, layout and financials are all correct.