At initial workspace access you are forced to set your password.
In case later you like to change it there are two options:
Click 'Forgot password?' link on the login dialogue, provide your email and a link to change the password will be sent to you.
2. If you are logged in the application open the settings via click on bottom left icon and choose 'Profile settings':
and select 'Account' in
When clicking 'Request password change' an email will be sent to your current email address. Using the link in the received email you can set a new password.