Keyboard for Hindi typing (Android Phones)
Most keyboards will work exclusively for Hindi and you'll have to change the keyboard app each time you wanted to type in English.
SwiftKey solves this problem and is of great help for multilingual people.
With SwiftKey you can type in English, Hinglish and Hindi at the same time.
Download it from the play store. Set everything up. Turn on auto correct. Go in "languages" and download Hinglish as well as हिंदी. If you can't read the script yet, memorise what हिंदी looks like by looking at it here and then go and download it in SwiftKey.
Turn on English, Hinglish and हिंदी(Hindi) simultaneously. Now all your Hindi words can be turned to devnagri. You type "Hindi" and it'll suggest हिंदी !
Comment if you face any problems.