Where if Not in Password App Can I Store App Passphrases?

Which Password App that you are referring to...

If you encounter any challenges with third-party applications, the best course of action is to directly contact the app developer for further assistance. Here's a brief guide on how to do it:

1. Identify the app developer.
2. Visit their website or app store listing.
3. Look for their contact information or support channels.
4. Clearly describe the issue you are facing.
5. Provide any necessary information they may need.
6. Follow their instructions and provide feedback.
7. Be patient and follow up if needed.

By reaching out to the app developer, you increase your chances of receiving accurate and personalized support for the challenges you're experiencing. To contact an App developer --> How to contact an app developer - Apple Support

This pic may help you if you are referring to the iCloud Keychain