Click on "My Accounts" and select "View" on the Account which you wish to have the password reset.
Click on "Actions".
Click on "Change password" then "Copy password" and paste the password somewhere safe.
You will receive a notification on the top of the page confirming the password has been reset.
Please note: If you navigate away from the action screen before copying the password, you will need to go through the process again.
You would need to then go and take the new password and change this on your MetaTrader application - either desktop or mobile application.