You can find your trading account password in three different places:
Notifications: Check the notifications at the top right of the platform for the notification called "Account created," which includes the initially set password.
Email: Search your emails for the message sent at account creation, which contains the initially set password.
Back Office: In the back office, click the menu option "Accounts," select the account you want the password for, and then click "change password" on the right side.