We need to have the Farm Tax Number for the customer to autofill on the invoice when we create one.

Welcome to the QuickBooks Community, kim-reddick-iclo.

Please note that you have the option to use improved custom fields to track the information that is most important to you. That said, you may add a Farm Tax Number field on the customer profile and enter the necessary details from there. This way, this info will autofill on the invoice every time you create a particular customer entry. 

Before doing the steps, please know that the process is only available in QuickBooks Online Advanced. If you're using this version, please follow the instructions below.

1. Click the Sales menu at the left panel, then Customers.
2. Find and open a customer profile.
3. Choose Edit.
4. Go to the Custom fields section.
5. To create a custom field, click + Add custom field. Then, enter Farm Tax Number in the Name field.
6. Fill out other needed info about the field, then select Save.
7. Enter particular info in the Farm Tax Number field.
8. Select Save to save your changes.

Once done, you can now go to the Invoice page and choose a specific customer. You'll then see that the custom field you added to their profile will automatically appear from there.

If you're not utilizing the Advanced, you can consider upgrading your plan to the said version. This way, you can smoothly use the enhanced custom fields.

Otherwise, you have to add custom field to your sales forms and manually enter the Farm Tax Number details. However, this process will not occur automatically when selecting a specific customer; instead, it will appear every time you make an invoice, regardless of who the transaction is with.

In case you need steps on how to view the status of your sales transactions such as open and paid invoices, you can read this article: View sales transactions in QuickBooks Online.

Don't hesitate to drop a comment below if you have other concerns about managing invoices in QBO. I'd be glad to assist you as soon as I can, kim-reddick-iclo. Keep healthy and safe.