A provisional patent application is an application which is the first step towards procuring a patent registration with the Patent Office.

No, filing of provisional Patent application is not mandatory and you can direct file non provisional patent also.

USPTO conducts examination on the “Provisional Patent Application” after the non provisional patent is filed, not before that.

Yes, filing of Provisional Patent application is cheaper than filing of non-provisional application.

Once you have started working on your invention and your research on the same is not complete, you can go for filing of “Provisional Patent Application”. You can secure priority date also through this application.

Filing of “Provisional Patent Application” is less expensive and less complicated. It provides you with priority date and gives you the chance of writing “Patent Pending” on your product.