I want buy apple care for AirPods Pro so how to buying?

Hi,

If those are indeed Apple AirPods Pro, you may reference the following to complete your AppleCare+ purchase:

• Apple Support App
• iPhone Settings > Bluetooth > AirPods “i” icon > AppleCare+ coverage available.

This applies only to the iPhone the AirPods are paired with.

• mysupport.apple.com
• checkcoverage.apple.com
• ARS
• contact Apple Support

It’s important to remember that products are eligible for an AppleCare+ plan, as long as the plan is purchased within 60 days of the products DOP.

https://support.apple.com/en-us/HT202702

https://support.apple.com/en-us/HT202741

Hope this helps!

Check this page: Buy an AppleCare plan - Apple Support

Hope it helps!