Video tutorial HERE.

In the new invoicing tool, here's how to add a contact to the invoice:

Under the Bill To section, click on the Search for Contact button and select the desired contact

To change how the contact information show up in the invoice, click on the Edit Details button

Here you can change the name, email, phone, and address. After that click on the Save Edits button. Please note: any changes made here do NOT affect the information saved in Contacts

After that, you can either apply the same information under Ship To section, or to add a different contact