i can buy diamonds in mobile legends using redeem card?

Do you mean by redeeming an iTunes Gift Card? If so, then yes. Redeeming an iTunes Gift Card creates a credit balance on your iTunes account, and you can use that credit to purchase anything in the iTunes & App Store as well as for paying your monthly iCloud subscription, as long as the credit amount covers the charge you are making.

Best,

GB

Sorry, not clear on your question. What do you mean by "redeem card"?

The article you linked from refers to iTunes Gift Cards. If that is not what you are asking about, and if it is easier to ask your question in your native language, then please feel free to do that so we can get your question answered.

Best,

GB

I've already answered that question. Yes, you can. Redeem it to your iTunes account, then you can make the purchases as long as they do not exceed the charges you are incurring.

GB