Outlook Web App (OWA) is— next to Outlook—probably one of the most popular ways of connecting to an Exchange server. Over the past Exchange editions, OWA has grown from a simple online mail viewer which could only be used with Internet Explorer to an online mail client offering a feature rich experience to anyone connecting with just about any web browser.
Depending on which browser and device you are using, your user's experience might vary. For a complete overview of the supported browser and the expected client experience, have a look at the following TechNet article:
http://technet.microsoft.com/en-us/library/jj150522(v=exchg.150).aspx
In order to make the following configuration changes, you will need to start the Exchange Management Shell.