How do I add new or existing customers when writing checks or bills

Thank you for reaching out to us, @wirtalapsw1. I'm here to help you add a new or existing customer when writing checks or bills in QuickBooks Online. 

The option to add new or existing customers is only possible for check transactions. You can only add vendors for bills. 

Here's how to add a new customer:

1. Go to + New.
2. Select Check.
3. Click on the Payee dropdown.
4. Then click + add new.
5. Under the contact type dropdown, select Customer.
6. In the Customer display name field, enter what you want to display for the customer (this is a required field).
7. Click Save.

For adding an existing one when writing checks:

1. Go to + New.
2. Select Check.
3. Click on the Payee dropdown.
4. Scroll down and look for existing customers.
5. Fill in additional information.
6. Then click Save and Close.

If you want to learn more about adding, editing, deleting, and merging customers in QuickBooks Online, you can check out this article: Add and manage customers in QuickBooks Online. 

If you have further questions about adding your customers, let us know by leaving a reply below. Have a wonderful day!