How do I add new fields to invoices for specifying additional information (Phone Number, Federal Tax, etc)?

To add new fields to your invoice, all you need to do is set up custom fields in your Settings. To create a custom field, follow the steps below:

• Click the Gear icon on the top right corner and select More Settings.
• This will take you to the Preferences sub-tab.
• Now click on the Invoices preferences and scroll down to reach the Custom Fields section.
• Enter the additional field that you want displayed on your invoice. You can add upto ten such custom fields for your invoices.
• Check Show in all PDF if you want the additional field data to be shown in the PDF. Click Save.

The new additional field will now be available when new invoices are created, as shown above.