Andriod marshmallow is new version of android,with extension of the core features and functionality of Android Lollipop. Some of the features of marshmallow:

1.Spot-on answers, fast: With a simple tap, you can get cards with useful information and apps that fulfil your needs.

2.Smart Battery: It has very strong battery backup support ,battery which works smarter,saves more.

3. When your device is at rest, Doze automatically puts it into a sleep state.

4. Great Control: All the apps and other things in mobile are controlled easily,which provides peace of mind to user.

5. Simplified security with your fingerprint: Your fingerprint unlocks your phone and lets you securely breeze through sign in, the Play Store and even in apps.

Detail Explanation:
1. Home screen
The same voice command functionality appears on the home screen via Google’s dedicated search bar, complete with the colorful, post-Alphabet Google logo

2. App drawer
The app drawer in Marshmallow went through a couple of changes during the developer preview process and appears in the final version as a vertical scrolling list as opposed to the paginated horizontal list from Lollipop.An endless vertical list means it’s easy to swipe right to the end of your app list

3. Notifications and Quick Settings
As with Lollipop, Marshmallow has a two-part notifications/Quick Settings area. A single swipe down from the top of the home screen will pull down the notifications shade, where your expandable notifications live. A second swipe down on this screen, or a two-finger swipe down from the home screen, will take you to the Quick Settings panel.

4. System UI Tuner
Once enabled, System UI Tuner will appear in the settings menu at the very bottom. It provides a few simple UI tweaks, including adding a battery percentage indicator to your battery icon, a customizable Quick Settings area and many more.

5. Animations and Easter Egg
Animations and transitions make up an even larger part of Marshmallow than they did in Lollipop. Transitions between apps, pages and settings are quite often accompanied by animations, as is toggling features on and off within the various settings and menus.

6. Dark theme and rotation support
Both the system-wide dark theme and support for a rotating home screen were removed from the final version of Marshmallow.

7. Google Now on Tap
Google Now on Tap basically shortcuts the need to search for additional contextual information and delivers it at any turn. Long-pressing the home button now activates Google Now on Tap, replacing the old gesture for Google Now from any screen.

8. Voice API and Assist API
Marshmallow also introduces a new Voice API to Android. Voice search and voice commands are central to Marshmallow.

9. Google settings app
Google settings are now a dedicated part of the settings menu. Here is where you’ll find privacy information, account preferences and more for your Google accounts. It’s also where you can manage your OK, Google hotword detection and ‘always listening’ mode.

10.Android Pay
Android Pay is one of a number of touchless payment systems including Apple Pay and Samsung Pay.

11. App standby
App standby identifies apps that haven’t been used in a while and puts them into a deep sleep, which is basically the same thing as disabling them in the settings..

12. Type-C and reverse charging
Marshmallow also supports the new standard, USB Type-C. Type-C cables are reversible and they also support faster data transfer and charging speeds.

13. Encryption
Marshmallow provides encryption support for better security.

14. Smart Lock
Smart Lock on Marshmallow provides options for unlocking your device or keeping your device unlocked depending on various intuitive scenarios.

15. Text selection
Marshmallow introduces an improved text selection setup.Instead of getting a temporary edit/share toolbar when highlighting text, in Marshmallow you’ll get a localized floating menu that offers three simple options: select all, copy or share.

Marshmallow is primarily about a few things: making Google services even easier to use; delivering better ways to access and manage apps; addressing core system weaknesses like battery life and security; and delivering more customization and user-facing controls to stock Android.