I bought beat studio3 but cannot redeem my 6 months free apple music

Hi Thadar123,

welcome to the Apple (user-to-user) Community.

Re: "I bought beat studio3 but cannot redeem my 6 months free apple music"

Wondering where you tried to redeem the music offer, and what happened ...

eg: an error message that may help troubleshoot.

Maybe check that Apple supports music subscriptions in your country or. region.

Availability of Apple Media Services – Apple Support 

If so, check you are signed in (to your device) with your Apple ID:

and

that the newest version of iOS or iPadOS, macOS, watchOS, or tvOS is installed.

Try redeeming from here, via "How to Redeem your offer"... and "Get started":

https://offers.applemusic.apple/six-month-offer

If needed:

Official Apple Support