OWA is now a central part of Office365 and ExchangeOnline and integrates directly into each user’s Office365 portal.
If the user has a subscription to the LyncOnlineservice, then OWA also displays their LyncOnlinepresence information.
In many ways, OWA planning is relatively simple.
OWA is always available to an Office365 or ExchangeOnline user unless you switch it off.
It will work with a range of browsers, including those on mobile platforms.
OWA also offers offline reading and composing of email messages on certain browser types
(Internet Explorer 10, Safari, and Google Chrome).