Your passcode is the key to your account. It has 6 digits, and you created it when you opened your account.
You use it to:
open the app (unless you use Face ID or a fingerprint)
sign in on a new phone
confirm every crypto transfer
close your account
It's not your card PIN. It's only for the ArtPay app.
Make it hard to guess. The app won't accept easy ones like 111111 or 123456. Pick something only you would know, and skip your birthday.
Keep it to yourself. Never tell anyone your passcode. Our support team will never ask for it.