Hi,
1. If you are talking about 'native' mobile apps, like Android apps or iOS apps, these apps have nothing to do with django. These apps have their own authentication systems you should investigate for each platform.
1. If you are talkin about 'mobile web apps', these are apps running in a webserver and accessed through a web browser. Being run in a web server means you can use django and you can use the same authentication mechanism used for desktop web apps. There is no difference.