I thought by that definition in faq, greenaddress is a multisig wallet.
Can someone show me a txid made by this wallet, it would be easily noticeable.
or explain why it says 2of2 account?
Greenaddress IS a multisig address.
2 of 2 means that BOTH signatures are needed to move funds in the wallet -- one of the user, and the other by green address.
TXID is like any other transaction, with the address starting with 3 indicating a p2sh address
This is a sample TX ID of a transaction made by a GreenAddress wallet:
.
https://blockchain.info/tx/e801ef473ed1f5e0fb541d5c8cfccc2418e3af2f5d398dc303ec60949fa2d15c