A patent provides a limited monopoly to make, sell, and/or use your invention. The patent term begins on the application filing date, so a timely-filed application can give you substantial competitive advantage. In addition, by disclosing your invention to the US Patent and Trademark Office, you establish a filing date that protects you against someone else filing an application for the same idea.

Any new and useful composition, process, machine, tool, and/or improvements to existing inventions may qualify for a patent.

After a non-provisional application is filed, the USPTO will assign an examiner who has expertise in the field to prosecute the application. The examiner will evaluate the specification and claims and perform a prior art search. Based on the search and evaluation, the examiner may generate one or more Office actions and/or a Notice of Allowance. Each Office action requires a complete response that may include claim amendments and/or arguments. After an agreement is reached regarding patentability of the claims, a Notice of Allowance will be sent and a patent may be issued after payment of the issue fee. 

A utility patent protects the way an article is used and works, while a design patent protects the way an article looks.

No. "Constructive" reduction to practice may occur, for the subject matter described in a patent application, when the application is filed.