How can I search customer details such as address lines or telephone numbers etc?

I'm glad to see you here, @communityoil. I can share some steps so you can view your customer's personal details.

In QuickBooks Online (QBO), you can pull up the Customer Contact List Report to see your customer's information. This contains columns for each customer's specific info such as phone numbers, email, billing and shipping address, etc.

Here's how to run the report:

1. Go to the Reports menu.
2. Scroll down to the Sales and customers section.
3. Click Customer Contact List.

Also to guide you in filtering data and personalising your report, head to the customise reports page at this link for detailed instructions. This also includes steps on how to export, send, and print reports. 

Please keep in touch if you need more assistance in getting your customer details in QBO. I've got your back. Have a good day and keep safe.