How to use the Tamil type writer keyboard. I know only that. Can I change the keyboard settings as tamil type writer key board. If it is possible How?
Please refer the answers here (includes links to questions on typing in Telugu and Hindi) and here (typing in Chinese). This is more an issue of having language / keyboard / font support in the operating system, than one related to LO.
There are many options available for you to type Tamil using the Typewriter method. One common option is to use eKalappai, a popular free software that is available here.