Hello there, anthony76.
I can see how the strange printing behavior you encountered prevented the letters and numbers from appearing on the invoices. I'm here to help and guide you to the right support that can address your concerns on time.
Based on the information provided, you'll have to double-check first your printer settings. This is to determine if the issue is on the device's setup. If it's configured correctly, printing problems could be fixed by installing an updated printer driver or by utilizing the OS X-bundled generic Postscript driver.
That said, I suggest contacting your device manufacturer or Apple support for further assistance. You can also perform the solutions in this article to resolve common printing issues: Troubleshoot printing problems in Safari.
To learn more about why Windows users are able to print with Adobe Reader and the steps to display PDF files in Safari, check these resources for the full details:
Keep me posted if you have other invoice concerns or additional questions about printing transactions. I'll get back to help you the best that I can.
