6. How to Setting Video Resolution
A profile is a collection of common video settings (size, frame rate, aspect ratio, etc…). Profiles are used during editing, previewing, and exporting to provide a quick way to switch between common combinations of these settings.
The project profile is used when previewing your project and editing. The default project profile is “HD 720p 30fps”. It is best practice to always switch to your target profile before you begin editing. For example, if you are targeting 1080p 30fps, switch to that profile before you begin editing your project.
The export profile always defaults to your current project profile, but can be changed to target different profiles.