Qifei on Nostr: 1) there are lots of verification provider. You can change it in Setting -> NIP-05. ...

1) there are lots of verification provider. You can change it in Setting -> NIP-05. And type in the field a string like name@domain.com . This string you can get from provider. Actually it is not important. But in some relays, any accounts verified by paid provider can post in the Global.
2) Your lightning address is a string,that is used to receive sats. Firstly, you click receive in your wallet, and set a number of sats. Then you will get a string for receiving or a QR code. This string you can use as your lightning address.