Hit the 'More' button near the bottom right of the screen to enter the 'Settings' menu.
General
Background - This option allows you to choose a different background for your Wunderlist.
Date Format - Here you can change the date format to fit your local standards. You must restart Wunderlist to apply the change.
Language - Here you can change the language to the one you prefer. You must restart Wunderlist to apply the change.
Add tasks by email - This option allows you to test our Mail2Task function.
Account
Edit - This option allows you to change your email address and/or password. You'll have to enter your current password to confirm the changes. If you have any problems, please have a look here.
Delete - This option allows you to delete your Wunderlist account. You'll have to enter your current email address and password to confirm the deletion.
Logout - If you wish to stop using Wunderlist for a period of time, or if you are having any problems, hit the 'Log Out' button. You can always log back in again using the main screen.