Shortly before the iPhone 6 was released, Apple published an official guide on how to transfer files and contacts from Android to iPhone.
The basics
The guide is divided into sections for Email, Contacts, Calendars and includes tips for transferring photos and videos: Your music should be imported into iTunes. Books and PDFs will find a new home in iBooks. Moving documents is easy and there's a quick guide on how to find similar or better apps.
For Email, Contacts, and Calendars, you can use Gmail, Exchange, Yahoo, or other similar services. All you have to do is add your Email Accounts, or use an app like “Copy My Data” for iOS and Android.
Logging into social networking sites will also import some of your contacts to iOS. For photos and videos, there are a few apps that can help, but it's not always easy to use a computer for this. The Photo Sync app for iOS and Android will come in handy.
To transfer your favorite songs from an old Samsung or Nexus,
Apple recommends a streaming music app like Pandora or Beats Music.
Detailed information can be found here.
