I'd like to invoice a supplier, but I can only invoice a customer. If I try to add my supplier as a customer, QB says ... Another customer or supplier, is using this name

Good day, @jonathan42.

To add a customer:

1. Go to Sales on the left menu, then click the Customers tab.
2. Click New customer on the upper-right corner.
3. Type the name, address and other necessary information.
4. Hit Save

To add a vendor/supplier:

1. Click Expenses on the left menu.
2. Go to the Vendors tab.
3. Click New vendor on the upper-right corner.
4. Type the name, address and other necessary information. (Make sure to add a character or symbol if you're adding the name as our customer).
5. Hit Save.

You can use this article for more information about the process: Error: The name supplied already exists. Another customer, vendor, or employee is already using this...

To learn more about merging supplier/customer accounts and the list of accepted characters in QBO, please visit these articles below: 

• How to merge accounts, customers, and vendors
• Acceptable characters

If you have other questions, feel free to reach out to us anytime. We're always here to help. Have a good day!