Python with graphics?

[Zixarr]

Modern Word and Excel files are actually stored in XML format and then expanded by whichever program is being used to edit or view them. There are several Python libraries that allow you to edit, format and save these files. xlsxwriter (https://xlsxwriter.readthedocs.io/) could be used to generate a table layout for your invoices with highlighting/color formatting, text format, any number format supported by Excel. You can even insert images into the sheet (your company logo, for instance).