Insufficient store credit for Apple Music subscription

Re: "Apple Music subscription: so i am add money to apple account by gift card and apple account

please tell me what am I do?

If you haven't used Apple gift cards with your account before:

You may want to check which payment methods Apple can accept in your country or region:

See: Payment methods that you can use with your Apple Account - Apple Support

See how to redeem an Apple Gift Card | Apple Support

How to redeem your Apple Gift Card, App Store Card, or App Store & iTunes Gift Card - Apple Support

Eg: says:

"Redeem a gift card on a Windows PC

1. Find the 16-digit code on the back of the card. For some gift cards, you may need to peel or gently scratch off the label to see the code.
2. Open the Apple Music app or Apple TV app.
3. Click your name at the bottom of the sidebar, then click Redeem. You may need to sign in with your Apple Account first.
4. Follow the instructions on the screen, then click Redeem."

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If you received a gift card by email

"To redeem a gift card that someone emailed to you,

open the email and tap or click the Redeem Now button."

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Re: "show me amount what I am added"

Learn how to check your Apple Account balance

You may need to allow 24 hours for account updates to come into effect everywhere in use.

You can also:

View your purchase history for the App Store and other Apple media services - Apple Support

On your Windows PC

1. Open the Apple Music app or Apple TV app.
2. Click your name at the bottom of the sidebar, then choose View My Account. You might need to sign in with your Apple Account first.
3. Scroll to the Purchase History section. Next to Most Recent Purchase, click See All. It might take a moment for your Purchase History to appear.
4. If you want to view more purchases, click "Last 90 days" at the top of Purchase History and choose another way to filter your purchases."

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If needed: What you can buy with your Apple Gift Card or Apple Account balance - Apple Support

How to Add an Apple Account Payment method:

Add a payment method to your Apple Account - Apple Support