Hi pfkohan,
welcome to the Apple (user-to-user) Community.
Re: "I recently purchased an Apple airpodpro 2nd generation two weeks ago.
then I discovered one of the airpods has malfunction":
Apple support has info. online that may be helpful:
You might begin by entering the AirPods serial number online to check your warranty and receive instructions:
Find the serial number of your AirPods - Apple Support
Enter serial number to:
Check Your Service and Support Coverage - Apple Support
You can then follow the onscreen instructions
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More info:
About Warranty: Legal - Hardware Warranties - Apple
Legal - Hardware Warranties - Apple
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Re: "I want to know how to send it to Apple for additional examination and how to change to a new one".
About Replacement : AirPods Repair & Service - Apple Support
More info: AirPods Express Replacement Service - Apple Support
Eg:
Learn how to send your AirPods, AirPods Pro, and Wireless Charging Case to Apple using Express Replacement Service - Apple Support
says:
After you’ve contacted Apple for a replacement, you’ll receive a kit that contains a replacement product with everything you need to return your original product to Apple.
or
If you decide to visit an Apple Store: a Genius Bar reservation is recommended:
Genius Bar Reservation and Apple Support Options - Apple
All the best :-)