lightning:email@example.com format is supported. Add your lightning wallet in the edit profile section.
Issue a Lightning invoice or you can also use
lightning:firstname.lastname@example.org on a note.
You can zap by clicking the ⚡️ button. Your mobile wallet needs to be registered on the device for the link to be recognised when you click it.
Lightning wallets are starting to implement the zapping feature. You could try
Wallet of Satoshi for mobile or Alby for desktop. The technical term is NIP-57 when checking for nostr zapping compatible Bitcoin lightning wallets.
The ⚡️ symbol is a
lightning:link to the user's Bitcoin address.
How to zap