It's good to see you here in the Community, waterpipe88.
I'm here to help ensure you can add your customers. As an initial step, let’s check to see if the browser has a full cache. This can often cause errors and prevent web pages from loading properly.
To start with, please open QuickBooks in a private or incognito window. This prevents the browser from saving your browsing data.
Here's how to open a private window in different browsers:
Google Chrome: press Ctrl + Shift + N
Mozilla Firefox: press Ctrl + Shift + P
Internet Explorer: press Ctrl + Shift + P
Safari: press Command + Shift + N
If you're able to add your customers via the private window, go back to the main browser and clear its cache to start with a clean slate.
I'm leaving you some recommended resources to guide more in manage your customers as well as your QuickBooks account
Help Articles for QuickBooks Online.
Edit customer information
It'll be always my pleasure to help if you have any other questions. Just keep me posted in the comment section down below.
