Hi there,
Thanks for reaching out to us here. I'll be happy to steer you in the right direction so you can get back to doing the things you enjoy.
First, I'd like to start off by troubleshooting this issue to determine if it's a browser-related issue. Clearing cache and cookies is a great way to clean your browser allowing it to work more efficiently. Here's an article that shows you how to do that: How to clear cache and cookies. For reference, here's a helpful article that shows you how to: Customize invoices.
I'll be one message away in case you need further assistance.