Im unable to make invoice. The system won't let me access to my costumer information

Intuit will probably get around to fixing it at some point. Or they'll blame your browser.

I'm here to provide ways to help you access the customer info on the invoices in QuickBooks Online (QBO), Clean.

I've replicated the issue and was able to select the customer on the invoice. Refer to the sample screenshot below:

In this case, I recommend accessing your QuickBooks Online account in an incognito/private window to see if it's a browser issue. Your browser's cache and cookies become corrupted, causing problems when accessing websites or opening files.

Please refer to the following keyboard shortcuts based on your browser type:

• Google Chrome: Ctrl + Shift + N
• Mozilla Firefox: Ctrl + Shift + P
• Microsoft Edge: Ctrl + Shift + P
• Safari: Command + Shift + N

If the private browsing session resolves the issue, clear the browser's cache to refresh the system. You can also use other supported, up-to-date browsers. Clearing the cache will remove stored data, including cookies, which may be the cause of the problems. 

Additionally, you can refer to this article to learn how to personalize sales forms in QBO: Customize invoices, estimates, and sales receipts.

Keep me posted if you have other questions about managing your invoice. I'll be right here to help. Take care.