This is referring to Argent X (browser extension recovery). If you want to prepare for your Argent mobile wallet recovery, please find the details here.
Recovery with seed phrase
You can find the seed phrase if you click on Settings icon in the top-right corner > Setup your account recovery (if you never set it up).
Once you save your seed phrase once, you can later find it in Settings (gear icon in the top-right) > Show recovery phrase.
Recovery with private key
It is impossible to recover your Argent X wallet with the private key.
If you have lost your seed phrase and have a private key only, you can try a CLI tool created to move assets from the lost wallet to a new one.
If you are using mac, there is a video with the steps from our developers, and here you can find a guide for Windows.
Advanced security setup
Advanced security of your Argent X wallet will be available soon.
What if I forget my password/lose my json file?
You will need to recover your wallet via seed phrase or advanced recovery option if you forget the password.