chore: describe the usage of the package better

Author: aminya

README.md

@@ -1,21 +1,25 @@
 # Code Format
 
-Format a selection of code using the `code-format:format-code` command.
-(Also accessible via context menu, or "Edit > Text > Format Code").
+## Usage
 
-When no selection is provided, the entire file is formatted.
+- By default the currently open file is formatted on save.
+
+- Format a selection of code using the `code-format:format-code` (`CTRL+SHIFT+C`) command.
+  (Also accessible via context menu, or "Edit > Text > Format Code"). When no selection is provided, the entire file is formatted.
+
+- For the languages that support on type formatting, the package is able to format as you type in the editor. You should enable this from the settings of this package (disabled by default).
 
 ![Code Format](https://raw.githubusercontent.com/facebookarchive/atom-ide-ui/master/docs/images/code-format.gif)
 
+## Developer Service API
+
 Code Format also provides APIs to:
 
-- format code as you type
 - format code on save (after you press save but before writing to disk).
+- format code as you type
 
 You can enable format-on-save using plain range/file providers from the atom-ide-code-format's settings
 
-## Service API
-
 Provide code format [Atom services](http://flight-manual.atom.io/behind-atom/sections/interacting-with-other-packages-via-services/) by adding one or more of these to your `package.json`:
 (Only the ones that you want to use; you don't need all of them!)