Tap Settings > Accounts > Add account > Email.

Type your full email address and password, then tap Next.
Select Manual.
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Email eg user@company.com
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Domain\Username Type your full email address again
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Password Use the password that you use to access your account.
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Exchange Server The server name for Office 365 for business is outlook.office365.com.
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Make sure the Use secure connections (SSL) box is checked.
Tap Done.
Depending on the company you might
receive a message about additional security features.
Select OK or Activate to continue.

Accept the defaults or make changes for how you want your account to sync on your device. When you're finished, swipe to the bottom and tap Next.
On the Set up email page you can change the name of your account. When you're finished tap Done.