ReSharper extends Visual Studio's native code completion (IntelliSense) with more advanced capabilities. For example, it narrows down the list of suggestions based on your typing, understands lowerCamelHumps abbreviations, suggests variable and field names depending on their type names and your naming style, automatically imports selected types and extension methods, and more.
Note on shortcuts
All keyboard shortcuts provided in this page are available in ReSharper's default "Visual Studio" keymap. For details on ReSharper's two keymaps, see ReSharper Documentation.