The Salesforce1 mobile app is an enterprise class out of the box mobile app built by Salesforce.com. It is available for all Salesforce users including the Chatter Free users. This app is available for both iOS and Android platforms; you can download and install it for free from the App Store for iOS devices, and from Google Play for Android devices.
This app supports both smartphones and tablet devices. Salesforce1, also available for users to use supported mobile web browser with supported devices, gives the same user experience as the installed app; for this option, you do not need to install the app on your mobile device.
The app will work for you out-of-the-box, and respect your Salesforce configuration, security, and customization, and is implemented without any efforts to reconfigure it. The only exceptions are AppExchange products...