What is a Project Charter?
The project charter is the document that formally authorizes a project to exist and names the project manager. It comes from the sponsor, not the PM, and it carries the authority: once it's signed, you can spend money, assign people, and make decisions in the project's name.
It stays deliberately high-level — business case, measurable objectives, key milestones, summary budget, and who the sponsor is. The detail lives in the project management plan, which comes later. On the exam, if the charter hasn't been signed yet, the project hasn't started — whatever the scenario tempts you to do first, the charter wins.
Worked example
A hospital approves a new patient-portal project. The CIO (sponsor) signs a two-page charter naming Sara as PM, stating the goal — cut phone-based appointment booking by 60% within a year — and a $400K budget ceiling. Sara now has the authority to pull developers from other teams. Without that signature, she'd just be a person with a good idea.