A Poster Design PLP file is a project file format used by Affinity Publisher, a professional desktop publishing software. The PLP (Publisher Layout Project) file contains all the elements of a poster design, including images, text, fonts, layout, and styles. Designers use PLP files to create high-quality posters for events, promotions, education, and advertising. This format allows full editing capability, making it ideal for revising and collaborating on poster projects. Since PLP files retain all layers and editable components, they offer more flexibility than standard image formats like JPEG or PNG. To open and modify a PLP file, you need Affinity Publisher. This makes the PLP format a preferred choice among professionals who want precision, print-ready quality, and complete creative control over their poster designs.