Write down the passphrase you want to use before entering it in your device.
Use a combination of words as a passphrase to have less trouble remembering it.
Use at least 12 characters in your passphrase, 24 characters offer more security.
If someone has access to your seed phrase, the passphrase will prevent them from taking your bitcoins.
Create a unique passphrase that nobody can guess but that you can remember.
If you lose the passphrase, you lose access to your bitcoins forever (if you also lose access to your device).
You cannot change your passphrase. You can only create a new one, which in turn will generate a new wallet.
The passphrase is required to recover your access to your bitcoins if your device is damaged, lost or stolen.