Yes. Lightning is a Layer 2 solution for #Bitcoin which allows faster payments and settlements.

Transactions are then grouped together and added to the blockchain at a later time for reduced fees. https://99bitcoins.com/bitcoin/lightning-network/

Yes - sort of. The transaction(s) occur off-chain, but they are ultimately settled on-chain. A Lightning channel/transaction is effectively a 2-of-2 multi-sig.

Here, this might help:

https://nydig.com/learn/the-bitcoin-lightning-network

Think of a lightning channel sort of like a bar tab; individual transactions while the channel is open are just shifting balance between two parties; either one can choose to close the channel with an on-chain operation, but all that's recorded on chain is the final split.