Tanglish - Tamil in English editor allows you to type Tamil words in English. Example:

English: vijay rajini kamal ajith suuriyaa
Tamil: விஜய் ரஜினி கமல் அஜித் சூரியா

Once you have typed you can share it via Twitter Email and other supporting apps. You also can copy and paste it into any apps of your choice.

Keymap and live keymap support provided.

NOTE: Disable auto suggest/predictive text in keyboard setting to get accurate conversion.