iPad app unable to select classes in transactions

Welcome to the Community, arob16. I appreciate your detailed information.

Since you're having issues selecting classes for transactions in the mobile app, I'd initially recommend trying to refresh data.

Here's how:
 

1. Go to Menu (☰), then Help & Feedback.
2. Tap Refresh Data.
3. Select Refresh.

There's also some additional troubleshooting you can try:
 

• Close and restart the app.
• Power off and restart your device.
• Check for updates in the App Store or Google Play and install the latest version.
• Update your device’s operating system to the latest available version.
• Switch between Wi-Fi and mobile data to check your connection.
  Uninstall and reinstall the QuickBooks app.

If the problem continues after trying each troubleshooting process, you'll want to get in touch with our Customer Care team. They'll be able to pull up your account in a secure environment, conduct further research with you, and create an investigation ticket if necessary.

I've included a detailed resource about working with the mobile app which may come in handy moving forward: Fix common issues in the QuickBooks mobile app

Please feel welcome to send a reply if there's any additional questions. Have a wonderful Thursday!