I deal with B2B customers and usually there is a different contact person for ordering and accounts payable. How can I add multiple contacts to same customer??

Welcome to the Community, Molives. 

I’ll share some details on how adding different contact information to one customer in QuickBooks Online (QBO) can help you and your business to be more organized.

When using QuickBooks Online (QBO), we can create sub-accounts and associate them with a Parent Customer. This allows us to keep track of multiple contact persons with different information, all associated with a specific customer. In that way, transactions will be categorized under the specified customer.

To create a sub-account, you can follow the steps below: 

1. On the left panel of your QBO account, choose Sales and select Customers.
2. Click on the green tab that states New Customer.
3. Enter the necessary information for your sub-customer. 
4. Mark the Is a sub-customer box. After marking the box, the parent customer dropdown menu will appear.
5. In the Parent customer ▼dropdown, select the parent account.
6. Marked check the box if you want to bill a customer together with their Parent Customer. 
7. Once done, click Save.

Please know that unlimited sub-customers can be created, but parent accounts are limited to four levels of sub-customers.

You can refer to this article for a complete guide to the steps I provided above in QBO: Add and manage customers in QuickBooks Online.

Once you have finished adding information about your customer, refer to this article for additional learning on creating customer-specific reports: Customize reports in QuickBooks Online.

Let me know in the comments below if there is anything else I can help you with managing your customer contact information in QBO. I’ll be here any time to assist you. Have a great day ahead.