There have been various new features brought into the system in preparation for GDPR, one of these is called 'Two Factor Authentication' which basically adds an extra layer of security to your account by letting you add a 4 digit pin to access your account.

The way to do this is by simply going to 'Settings' which is accessed via the 2nd icon from the left in the top right of the screen, and then 'general' and you can then set this pin code up from here.