The Vault has many features that make designing easier and among these is providing a common place to place shared library files. Common parts, iParts, iAssemblies are commonly stored and shared from the Vault. Inventor 2014 offers the ability to place iFeatures directly from the Vault into your part design so now it is a good idea to also store iFeatures in the Vault.
It is up to you if they are entered them into a library folder or as a folder under the Designs folder. I like to keep all standard assemblies, parts, iParts, iAssemblies and now iFeatures in library folders to make sure they do not get edited by mistake.
Make sure you add the iFeature path to your Inventor Vault project file either as a Library folder or a Frequently Used Subfolder if you decide not to place the iFeatures in a library folder. Make sure you have also replaced the Inventor Vault project file in the Vault so others can "Get" the updated project file.
The process of placing an iFeature from the Vault begins by selecting the iFeature from Vault icon located under the Manage tab on the Insert panel. The process is the same from this point on.
I like to make a shortcut in the Select file from Vault dialog box to make the search as easy as possible but you can use any search method you desire to find and place you favorite iFeature.