Withdrawals to trusted addresses do not require two-factor authentication even if it is enabled for your account (and we hope it is!).
The main use of trusted addresses is automated withdrawals with our Transfers API, but you can use them for fast withdrawals from the web interface as well.
All your current trusted addresses are listed on the respective page in your Xena account.
To add a new trusted address specify the cryptocurrency and the address:
You will be asked for your 2FA code to proceed.
Deleting a trusted address is also straightforward — just click on the "Delete" button from the desired address.