i redeemed a 500 apple gift card. where do i find it to verify ?

The article "What type of gift card do I have?" explains the different kinds of gift cards Apple uses, has links on how to redeem them, and what can be purchased with each kind. Click on the link --> What type of gift card do I have? - Apple Support

If it was redeemed to balance, read this article about how to check your Apple ID balance.--> Check your Apple Account balance - Apple Support

- If you think that your Apple ID balance is incorrect, sign out of the App Store or iTunes Store, then sign back in and check the balance again. If you still think that the balance is incorrect, check your purchase history to see if a subscription renewed or you bought an item that used the funds. Read this support article for directions about how to see your purchase history in the App Store or iTunes Store [mobile device, computer, or web] --> View your purchase history for the App Store and other Apple media services - Apple Support

If you still have problems:

Click here --> Choose your country or region - Official Apple Support Select your country, then a product. If you don't see one that handles your issue then keep experimenting with selections until you reach one that gets you a chat session or a telephone call and get the representative to redirect you.

or:

Contact Apple for support and service --> "See a list of Apple phone numbers around the world."

Click here --> Contact Apple for support and service - Apple Support

If you redeemed it to your AppleID, the amount will be reflected in:

Settings -> AppleID [Name] -> Payment & Delivery

The amount will be listed under “Payment Methods” and be included on the “AppleID” line.