My Custom fields stopped not showing on invoice... https://www.dropbox.com/s/4cv1vviits9xno6/No%20Custom%20input%20on%20invoice.pdf?dl=0 - How do I get this back?

Let's go ahead and check the custom fields setup, Supermuls19.

Just follow these steps:

1. Click the Gear icon.
2. Select Account and settings.
3. Go to the Sales tab. 
4. Click the Pencil icon in the Sales form content section.
5. Under Custom fields, ensure both Internal and Public boxes are checked.
6. Click Save, then Done.

Once done, try to create the invoice again and check if you can see the custom fields. If you're still unable to view them, let's check the invoice template. Here's how:

1. Click the Gear icon.
2. Go to Custom form styles.
3. Select the template, then click Edit.
4. Go to the Content tab.
5. Click the Pencil icon in the first row of the template.
6. Under Display, click Custom field.
7. Ensure that all field boxes are checked.
8. Click Done. 

For more details, you can go over this article: Customize invoices, estimates, and sales receipts in QuickBooks Online.

If you need more help with this, don't hesitate to reach out to us again. We're right here to assist you.