A free app for Android, by Rough Coder.
This free and user-friendly app allows you to type in Bangla. Using this, you can easily input and output Bengali characters from anywhere.
Parboti Bangla Keyboard has a built-in database containing the most common letters and words. It is very easy to use and features a phonetic layout option for efficient typing. You can also choose from 15 different themes Additionally, it has a handy suggestion mode for faster texting. You may set this keyboard as your phone's default keyboard. Parboti Bangla Keyboard is available for free on the Google Play Store.