How do I fix an update that just happened that caused custom invoice fields to no longer show up in our mobile version of Quickbooks Online?

The support you spoke with is correct about transitioning all QuickBooks Online products to the new invoice layout, debbie.

Concerning adding a custom field through the mobile app, we have an ongoing investigation into this and have asked the engineering team to look into the issue. However, since they are working on this internally, please know that we cannot provide a turnaround time regarding their efforts.

Moreover, I recommend contacting our QuickBooks Support Team to ensure you'll get an update about the resolution status. This way, they can add your company file to the list of affected users. You can follow the steps below by logging your company file on a web browser: 

1. Sign in to your QuickBooks Online account.
2. Click the Help button.
3. In the QuickBooks Assistance chat box, select Talk to a human and or tap the Contact Us button at the bottom.
4. Then, type in your reason for contacting us in the What can we help you with? Box and click Continue.
5. From there, choose a way to connect with us; either to Chat with us, get a Callback, or call our support line directly by getting our Phone number.

Additionally, refer to this article for other options when contacting them. You can also scroll down to the bottom to take note of their support schedule and hours: QuickBooks Online Support. 

In the meantime, you can create these custom fields by accessing your QuickBooks through a web browser. Here's how:

1. Go to the Gear icon and select Custom fields.
2. Click the Add field, and enter a Name.
3. From there, select the All Sales Forms checkbox. Then, turn on the Print on form if you want this field to appear when printed.
4. Then, hit Save.

We appreciate your patience while we’re working on this one. Please know that the Community always has your back if you have additional questions about QuickBooks. I'll be right here to help.