I want to know what the charge for $21.41 is for

Call Apple and ask. We don't know. We're users just like you.

Apple Store Customer Service at 1-800-676-2775 or visit online Help for more information.

To contact product and tech support: Contacting Apple for support and service - this includes

international calling numbers..

For Mac App Store: Apple - Support - Mac App Store.

For iTunes: Apple - Support - iTunes.