If you are using a BlackBerry 10 device, you can follow these steps.
On the home screen, select Settings.
Select Accounts, then Add Account.
Select Email, Calendar, and Contacts.
Type your email address and select Next.
Type your password and select Next. The Looking up connection information message should display.
If your connection information is found, select Done.
If you see a message recommending that you use advanced setup steps, start again and select the menu icon beneath the Email Address box to access advanced setup options instead of selecting Next.
On the Advanced Setup page, select Microsoft Exchange ActiveSync.
In Description, give your account a name.
Leave the Domain field blank.
In Email Address, type your full email address.
In Username, type your full email address.
In Password, type your password.
In Server address, type outlook.office365.com.
Select Next. The Checking for supported services and policy information message displays.
If your account is successfully connected, select Done.
If you are using a BlackBerry 7 or earlier device, you will need to connect your Office 365 account using POP or IMAP.