I own the minecraft bedrock edition on mobile and it is connected to my microsoft account saying that I own it but when i go to the minecraft launcher on PC it says i need to buy it and I dont know why

The version on both Google Play and Apple's App Store are independent of the bundle for the desktop editions of the game (Java/Bedrock).

Hi!
Thank you for your report!
However, this issue is Invalid for the bug tracker.

Minecraft Bedrock Edition on mobile is a separate purchase from the PC version. You can't transfer the license from mobile to PC. You'll need to buy the PC version separately.

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