Hi there! I understand you're trying to add a membership card in the Folio app on your iPhone with iOS 18.5, but you don't see the option in the list anymore. Let's get that sorted out together.

To make sure I guide you in the best way, could you please confirm a couple of things for me?
1. When you say the option to add a membership card is missing, are you referring to the "+ Add Card" button in the Folio app or somewhere else?
2. Have you recently updated the Folio app or your iOS version before this issue started?
3. Are you trying to add a new membership card by scanning it or entering details manually?

Meanwhile, here are some general steps that might help:
1. Check App Update: Go to the App Store and ensure your Folio app is updated to the latest version. Sometimes missing features are resolved in updates.
2. Restart the App: Close Folio completely (swipe it away from the app switcher) and reopen it. Sometimes that refresh helps options reappear.
3. Look for Card Categories: In Folio, card types like credit card, ID card, gift card, and membership/loyalty card might be listed under separate categories. Double-check if membership cards might be nested elsewhere in the interface.
4. Reinstall the App: If you suspect the app has corrupted data or settings, uninstalling and reinstalling Folio can reset configurations and bring back missing options.

If none of these work, it might be a glitch or a temporary removal of that option in the current app version. Folio’s support has mentioned that the only workaround sometimes is deleting and re-photographing cards under correct categories, but that’s more for managing existing cards.

Let me know what you find, and I'll help you take the next steps. Also, if you want, I can help you use an alternative way to add membership cards via Apple Wallet directly, if the Folio app is giving trouble.

Are you satisfied with this approach, or do you want me to look deeper right away?