I IMPORTED A CUSTOMER LIST FROM EXCEL SUCCESSFULLY. I NOW HAVE SOME MORE CUSTOMERS AND WANT TO IMPORT THEM. WILL THE SECOND IMPORT OVER-RIDE OR ADD TO THE FIRST IMPORT?

Pleased to have you here, @rms0304.

Let me share some information with you on how importing works in QuickBooks Online.

When you import your customer's list to QuickBooks, it will not override the formation that was already recorded in your account.

Here's how:

1. Go to the Gear Icon.
2. Choose Import Data.
3. Select Customers.
4. Browse for the file you'd like to upload or download a sample file to get a feel for the mapping before you upload the actual file.
5. Click Next.

For additional insights, you may check out this article: FAQs about importing data to QuickBooks Online.

If you need further help with importing your customer's list, I'd recommend contacting our Customer Care Team. A specialist will be able to further assist you via secured remote access session.

Here's how to contact us:

1. Go to the Help menu.
2. Click Contact Us.
3. Under How can we help?, type in your "Import Customer's List".
4. Hit Continue.
5. Click Get our phone number to contact us.

Keep me posted if you have other questions about importing lists in QuickBooks Online. I'd be happy to answer all your inquiries.