The patent application is applied upon filing a written application to the relevant patent office. The applicant may be inventor alone or his/her legal representative. The application must then include a description of how to create and use the invention, it must contain detailed information for a person skilled in the technical field how to create and use the invention. In some countries there are requirements for the provision of specific information, such as the usefulness of the invention, the best way of implementation of the invention known to the inventor, or a technical problem or problems solved by inventor. There may also be drawing/s provided by inventor.

After filing an application, the application is often called as a patent pending. Although this term does not provide legal protection and thus a patent cannot be enforced, it provides a kind of warning for possible offender that in case the patent is granted, he/she may be liable for damages.