It depends on which Nostr client you use? When you click on the "Tip" button it should give you couple options, like showing lightning QR code that you can scan

It depends on which Nostr client you use? When you click on the "Tip" button it should give you couple options, like showing lightning QR code that you can scan with any lightning wallet, opening your wallet directly, or opening the extension (Alby is the main one).