How can i register my airpods pro?

Do you mean how do you pair and connect them to the iPhone or your other device? If it's an iOS device or Mac, you should be able to just open the Airpods case (with the Airpods inside) and hold it close to the iPhone or device and it should see them and you can connect. Otherwise, put both Airpods in the case and close the case. Open the case again and hold the round button on the back of the Airpods case for 15+ seconds or until the light blinks white. You should then be able to pair them as they will be in pairing mode.