Allowing support login gives the Float team access to your account. Generally we ask you to allow access when we need to go in and fix something in your account. You can allow and disallow support login whenever you want.
Simply go to the menu for your settings within Float. Here you will see a tick box to 'Allow Support Login', ticking this box will enable support login and you will then need to confirm this by entering your password.
Similarly to disable support login simply untick the box and enter your password to confirm.