Some popular Bitcoin Lightning wallets, like Muun, don't support email-like Lightning addresses. This app allows paying to such addresses by turning them to convenient invoices. It doesn't add any extra fee to your payment. This utility is launched when you interact with addresses in your browser or other apps. Here's how it is done: Clicking an address Sometimes, a Lightning address is a clickable link, just like an email. When you click it, LN Address to Invoice appears. Selecting an address Often a Lightning address is just a text. In this case, select it and in the appeared system menu look for the "Send sats" action. Copy-pasting an address You can always just copy an address and paste into LN Address to Invoice with the Paste button in the header of the intro screen, or with the "Paste address" launcher icon shortcut.