Bitcoin (Lightning Network) Invoice

[MogulX]

I try to withdraw btc to my electrum wallet with Lightning Network.
On the send side I've been asked for an invoice of the receiving side.
My question is - what are the steps I need to perform in order to
generate invoice?

[BlackHatCoiner]

You should see this button in "Receive" if you've enabled Lightning:

To receive money in the Lightning Network you need to have some receiving capacity. In Electrum, when you open a channel, you only have the equivalent of the amount deposited as sending capacity. You'll have to spend some to increase your receiving capacity. For instance, you can exchange LN-BTC for BTC in boltz.exchange.

[nc50lc]

First, you need to open a channel.
It's only available for SegWit Electrum wallet (addresses start with bc1 and not a '2fa wallet'), if your wallet is of any other type, you can't.

Secondly, you need inbound capacity to be able to receive funds through lightning.
You can gain inbound capacity by sending some of your funds or by using the "swap" feature in the channels tab (it uses the same backend as the one suggested above).
The latter comes with a fee and it'll send some of your lightning funds to your on-chain funds.
You can check how much you can receive in the 'channels' tab: "can receive X. BTC".

Lastly, if the requirements above were already satisfied, use the 'Lightning' button in the receive tab instead of 'New Address'.