Once you’ve finished a map design, you can export your map for use in other applications. You can export the entire world or choose a smaller region by setting the bounding box. TileMill can export MBTiles, PNG and PDF and each format has different advantages.
Use MBTiles to export your project as a pannable, zoomable map just like the preview you see in TileMill. You can upload MBTiles to MapBox Hosting directly from TileMill. You can also save MBTiles files and host them yourself with TileStream or transfer them to MapBox for iPad for offline access.
Use PNG to export a static image of your map. This format is useful if you want to add a snapshot to a word processor.
PDF provides a vector-based export of your map, which is useful if you’re designing maps for printed material.
SVG provides another vector-based option for exporting your map. PDF and SVG output should contain very similar content but SVG is often supported by drawing programs natively (does not require conversion upon import).