GeoPackage

QGIS 3 has chosen GeoPackage as its default format. This is an open format, unlike the Shapefile, which is proprietary. GeoPackage also supports rasters. It is built on a SpatiaLite database, has no file size limitations, and works as one file. The format was developed by the Open Geospatial Consortium and is increasingly being adopted by organizations around the world. A GeoPackage  has a .gpkg extension, which unlike the Shapefile has several extensions.