Create your A3 landscape design document for PDF export
How to Export to PDF
Click ↓ Print to PDF below.
In the print dialog, set Destination to Save as PDF.
Set Layout to Landscape (horizontal).
Under More settings, enable Background graphics (or "Print backgrounds").
Set Paper size to A3 (if available).
If arrows or overlays are misaligned in your PDF, make sure you are exporting at 100% scale and using Chrome or Edge for best results.
How to use
Click any text area to edit (placeholder text will disappear). Drag & drop images into upload zones. Toggle Preview to see all pages as thumbnails.