[bigmanwalter]

I have a LibreOffice spreadsheet which I fill out my hours in. I also have a Writer document with my invoice layout and an embedded spreadsheet which lets me add line items and automatically calculates taxes. Easy enough to export to PDF. I keep all invoices in a specific directory, their filenames starting with the date and client name for easy discovery. I add the word '-PAID' to the filename once the invoice is paid by the client.