extract invoice number

You can do that with a script. However, you would have to iterate over every word on the page(s) to find the relevant information. There is no easy way to jump straight to one location and get just the word at that spot. There are ways to crop down the page to your target area before you itereate over all words (and in this case, you only get those from the cropped area), but you would then have to revert the crop to get your original page back. It's a lot of work, but it can be done. If you don't have spripting experience, it may be easier and cheapter to hire somebody to do that work for you.