Add initial guide for Litecoin MWEB

docs/cryptos/litecoin.md

@@ -12,8 +12,45 @@ Official Website: [litecoin.org](https://litecoin.org/){:target="_blank"}
 
 We automatically generate new Litecoin addresses after each use for better privacy. Previous addresses continue to work.
 
+BIP-39 seed type is generated by default, with an option to change to Electrum seed type in the `Advanced Settings` on the creation screen.
+
 We use the same derivation scheme as Electrum: `m/0/x` for receive addresses, and `m/1/x` for change addresses.
 
 ## Seed format
 
-Litecoin wallets only currently support being created using the Electrum seed format. We support restoring seeds generated in the Electrum and BIP-39 seed format.
+Litecoin wallets only currently support being created using the Electrum seed format. We support restoring seeds generated in the Electrum and BIP-39 seed format.
+
+## MWEB
+
+{: .friendly}
+Intoduced in version 4.20.0
+
+MWEB (MimbleWimble Extension Block) is an addition to the Litecoin blockchain that runs parallel on an extension block, using the MimbleWimble protocol.
+
+MWEB provides extra privacy through **Confidential Transactions**, **Stealth addresses**, and **CoinJoins**
+
+### Scanning
+
+In order to enable MWEB, tap the switch on the "MWEB" card to start scanning MWEB blocks.
+You will receive a warning about data usage, and the time it will take to download the needed data to use MWEB.
+
+{: .note}
+You will only need to download this data for MWEB once, regardless of how many Litecoin wallets you have.
+
+[![MWEB Scanning](./mweb.png){:width="32%"}](./mweb.png)
+[![MWEB Warning](./warning.png){:width="32%"}](./warning.png)
+
+The wallet will start downloading the needed header data. Once it's fully synchronized, you will be able to "Peg-in" your normal Litecoin inputs into MWEB by sending your balance to your MWEB address.
+
+If you would like for MWEB to be automatically enabled after wallet open, please toggle an option under Menu -> MWEB settings -> “Set MWEB always scanning” to on. Silent Payments scanning will automatically toggle on if there are new blocks to scan and toggle back off when it’s finished.
+
+[![App menu](./menu.png){:width="32%"}](./menu.png)
+[![Toggle always scanning](./alwaysscan.png){:width="32%"}](./alwaysscan.png)
+
+### Receiving
+
+In order to receive an MWEB transaction, you must give the sender your MWEB address, which can be found by switching the address type to MWEB by opening the `Receive` screen, tapping on the `Receive` text at the top, and switching the address type to `MWEB`. When you want to receive the transaction in the wallet, you must enable Silent Payments scanning.
+
+### Sending
+
+You can send Litecoin to an existing MWEB address using the same flow. No extra work is required to send to an MWEB address, the MWEB daemon will handle the transaction submission to the MWEB network.