These days, every web page contains a scripting programming language called “JavaScript” that runs in the visitor’s web browser. If it is disabled, the functionality of the website becomes unavailable or limited. So if you are facing the same issue with Invoice Office, then turn on the JavaScript.
Learn how to turn on JavaScript
Secondly, if you are not able to preview the document or invoice you created, then enable the pop-ups in your browser.
Learn how to enable pop-ups in your browser