How do I connect my account to Dropbox

Click on 'Settings' then click on 'Apps' - you will see the option to link your UK Postbox account to Dropbox.
Once selected you will be taken to a Dropbox page, 'Sign in to Dropbox to link with iPostalMail'. You can then continue by signing in, which will set up a new Dropbox folder in 'Apps', called iPostalMail which is where your new scanned will be uploaded when added to your UK Postbox account.