This question suggests that you are new to project management... The project charter, my friend, IS the project.
The project charter...
...defines the project vision, the project goal, and its objectives. It will also describe the product or service that is the fruit of this project.
...defines the project's critical success criteria.
...includes the scope of the project: what should be done and what should not be done.
...lists all the stakeholders involved in the project, and includes the stakeholder map.
...includes the potential risks/issues, the project constraints.
...includes the list of all the major milestones.
...lists all the assumptions about the project.
...lists the resources that are going to work on the project.
...and last but not least, is essential for the project to start, because the client has to approve the project charter in order for the work to start.