1. An ESRI Shapefile (SHP) import requires at least three files in the same directory, with the same name and following extensions: .SHP (stores geometry), .SHX (index file), and .DBF (stores database attributes for the geometric data).
In addition to these three required files, you can have more files with other extensions (for example, a .PRJ, which stores projection information).
2. A MIF (MapInfo Interchange Format) file import requires two files in the same directory, with the same name and following extensions: .MIF (stores geometry) and .MID (stores database attributes for the geometric data).
3. A GML import requires at least two files: the data file, typically named .GML or .XML, and the schema file, typically named .XSD. Version 2.1 and 3.1 of GML are supported.