Trading passwords are crucial; if leaked unintentionally, they should be changed immediately to prevent losses.
Typically after opening an account with a broker, brokers provide a login backend where users can change passwords and manage deposits/withdrawals among other operations.
Alternatively, password changes can also be performed via trading software terminals:
After logging into your trading account in the terminal navigation bar select account then right-click and choose “Change Password” for password modification.
MT5 operations are similar to MT4.