Sometimes for some reason the Private App button doesn’t show in Xero http://prntscr.com/r3jkjm but if you clear your cache and cookies it should do so. I just checked and had to log in twice to Xero as the first time it didn’t show as the url must be this https://developer.xero.com/myapps?privateAppCreation=true and not https://developer.xero.com/myapps/ which doesn’t show it any more.
