Go to Motorola support page
1.- Select Country.
2.- Drop down and Select Carrier
3.- You can easily learn which model number you have. Go to your device’s Settings and select About Phone.
Software updates will be sent to your phone automatically over-the-air (OTA) as they become available. You can manually check for updates:
To check for available updates over-the-air (OTA update):
1.- Click 
2.- Select Settings app
3.- Select System
4.- Click Advanced option
5.- Click System Updates
If an update is available, follow the instructions on your phone to download and install it. Once updated, your phone will restart to complete the installation.
To find the Android version on your phone:
1.- From your phone’s home screen, touch the , then click Settings > System
2.- Scroll down and click About phone
3.- Find your phone’s Android version