Preserve the quiet zone
A module is one small cell in the QR grid. Standard QR codes need a blank quiet zone at least four modules wide on every side. It is measured relative to the cells, not as a fixed number of millimeters.
Keep this margin in the exported image and outside the reach of titles, borders, illustrations, and cutting lines. Choosing a larger margin in the generator can provide extra separation in a busy layout, but it does not replace a sufficiently large QR pattern.
Choose size for the pattern and viewing distance
There is no single physical size that guarantees every phone will scan every code. A long vCard can have more modules than a short URL; at the same overall width, its individual cells are smaller. Viewing distance, focus, lighting, and printer resolution also matter.
As a layout example, a 29-module pattern with four-module margins uses 37 module widths in total. If the entire image is 37 mm wide, each module is 1 mm wide. Treat this as a way to understand scale, not as a required or guaranteed print size.
Export clean artwork
SVG keeps the shapes as vectors and is useful when a design will be resized. PNG is a practical lossless image choice. JPEG compression can soften cell edges, so inspect it carefully if your workflow requires that format.
Use dark modules on a light, opaque background. Avoid placing the image over a photograph or stretching it into a rectangle. Selecting 1024 pixels instead of 512 pixels changes the raster image size, not an automatic millimeter measurement on paper.
Check the finished sheet
Set up A4 or US Letter in the Print Designer, choose the intended physical dimensions, and ensure the repeated cards fit. In the browser print dialog, match the paper size and use actual size or 100% scaling.
Print one copy on the material you intend to use. Measure it, scan from a realistic distance, and repeat under the expected lighting. Glossy surfaces, folds, poor ink coverage, and trimming can affect a result that scanned correctly on screen.