Filing a provisional patent application establishes an early filing date for your invention. Further, you get patent pending status for a period of 12 months. It also allows you to use the term “Patent Pending” in connection with the description of the invention.
Provisional patent application is an inexpensive route to protect your invention for a period of 12 months.
A provisional application includes a specification, i.e. a description, and drawing(s) of an invention (drawings are required where necessary for the understanding of the subject matter sought to be patented.
Please note that the provisional patent application does not mature into an issued patent. For that, you need to file a regular non-provisional patent application within one year from filing the provisional patent application.