Many companies inventors choose to file a provisional application. What is a provisional application and why should you choose to file or not file one? Basically, it's a cheap and quick way to jump in line.
A provisional application is a patent document which fully discloses your invention. It lasts for one year and is not reviewed by the patent office. Why then would you want to file an application that will not be reviewed by the office? Because time is important and the filing is less expensive. Firstly, as an inventor, you want your application filed with the patent office as soon as possible. If someone else invents and files an application for your invention before you have filed, you have probably lost your ability to patent your invention. Therefore, getting the earliest possible filing date is urgent. Secondly, you have one year to test the market for viability of the invention in commerce, decide if vital improvements are needed for the device, or consider other inventions which may take a higher priority.
Provisionals are not required to have claims. Adding claims to a provisional is up to the patent attorney and client to decide. When non-provisional time comes, they will need to be written and included.
At the end of the year, you need to file a non-provisional application in order to continue with your patent. You will claim priority to the earlier-filed provisional application and receive the filing date of the provisional.