First step, you should do the patentability search for your invention. You can take help from Patent Agent/Patent Attorney for conducting patentability search.
After that, the invention description is written in a specific format as needed by the patent office, and it will contain Title, Abstract, Background, technical description and Claims. The patent specification is filed at patent office to obtain patent application number, and patent application will be published after 18 months from filing date, and next step examination (offical action) to scrutinize the novelty of invention and other requirement of patentability.
In case, any objection comes during official action, we need comply the objection to allow the patent application to grant. Finally, the patent will be granted after allowance of patent application.

