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+# 13.4: Generate a Payment request.
+
+> :information_source: **NOTE:** This is a draft in progress, so that I can get some feedback from early reviewers. It is not yet ready for learning.
+
+> :book: ***What is an invoice
+
+Almost all payments made on the Lightning Network require an invoice, which is nothing more than a request for payment made by the recipient of the money and sent by different means to the user who will pay.  The format for a Lightning invoice uses bech32 encoding, which is already used for Bitcoin Segregated Witness and all payment requests are single use.
+
+An invoice is made up of two parts,  one is human readable and other is 
+
+- Human readable part: `ln` + (`lnbc` for Bitcoin mainnet, `lntb` for Bitcoin testnet, and `lnbcrt` for Bitcoin regtest) + data amount
+      
+- Data part : UNIX Timestamp + tagged parts include a payment hash, the pubkey of the payee node, an optional description of the payment, an expiration time, and some extra routing information.
+
+For this example we've created a second lightning node using LND implementation.  We will refer to this instance using `lnd$ ` prompt shell to indicate place where we'll generate LND commands.   If you want to reproduce this steps you should use Bitcoin Standup to create a second machine and install LND.
+
+
+