Hi there! I see you're trying to purchase a subscription in the Vita Mahjong app for features like refresh and hints but can’t find the option to do so on your iPhone running iOS 18.6. Let's get this sorted out.

First, could you tell me a bit more about what you've tried so far? For example:
- Are you seeing any options in the app menu related to subscriptions or in-app purchases?
- Have you checked the App Store purchase settings on your iPhone?
- Is the app up to date with the latest version installed?

Meanwhile, here are a few steps to try that usually help in such scenarios:

1. Update the App: Go to the App Store, tap your profile icon, and check if there is an update available for Vita Mahjong. Sometimes subscription options only appear after updating to the latest version.

2. Check In-App Purchases Settings:
- Go to Settings on your iPhone.
- Tap Screen Time > Content & Privacy Restrictions.
- Make sure that In-App Purchases are allowed.

3. Look for Subscription Options Inside the App: Open Vita Mahjong, then go to the settings or main menu. Look for labels like "Store," "Subscribe," "Remove Ads," or similar. Sometimes subscriptions are found under "Remove Ads" or “Premium” sections.

4. Sign in with the Correct Apple ID: If your App Store account is different from the one used previously for purchases or subscriptions, the app might not show the right options. Make sure you are signed in with your usual Apple ID.

5. Restart the App and Phone: Close Vita Mahjong completely (swipe up in the app switcher), then restart your iPhone and reopen the app. This can refresh the connection to the App Store.

If these steps don’t reveal subscription options, there might be an issue with how the app is displaying the purchase options on your iOS version.

Would you like me to guide you through these steps now, or did you already try some of them? Also, any error messages or missing buttons you noticed could help me understand better.

Looking forward to helping you get those refreshing hints!