First, go to the Control Centre at the right top, then select Settings and Privacy:
The submenu Administration must then be selected.
To change the password
On the page there is a field to change the password, for security it must be repeated. Please note, the password must also be entered in order to change it:
To change the mail address
At the bottom of the page there is a field to change the mail address:
Note: The mail address must first be confirmed, for this purpose an activation mail will be sent to the newly specified mail address. Afterwards we still have to activate the new mail address manually.