Think of Personas as different ways of working within Affinity Photo. If you want to work purely with core photo editing tools you can edit in the default Photo Persona. However, Affinity Photo packs a punch with additional Personas that each offer either a specific design environment or analogous toolsets, features or functions.
Naturally, an Export Persona is always at hand to export your design.
Here's an overview of the set of Personas available to you:
You can switch between Personas with a single click, with the workspace tools and panels changing to that Persona's way of working.