On the “choose a mail account to add” page, select Exchange and then click Continue.

Near the bottom, left hand side of the window, click the (+) sign button.

From the Mail menu, select Preferences, then the Accounts tab. If you already use Mail, you will need to add your new account.If you receive the Wizard, skip to step 3. If you have not opened Mail before, you will see a Wizard to walk you through this process.

Your old mail account should now be removed.Verify you wish to delete the account by clicking OK.Once the Internet Accounts window opens, make sure your Exchange mail account is selected, then click the (-) sign in the lower left hand of the window.If you receive a prompt that the account is shared by other applications on your Mac, click the Internet Accounts button. Click to select your account, then click the (-) sign button on the bottom, left hand side of the window. Your OU Exchange mail account should be listed on the left side of this window. From the Mail menu, select Preferences, then the Accounts tab.To remove your old OU Exchange Mail account, open Mac Mail.If you have your OU Exchange mail account set up in Mac Mail, please do the following to remove your old account and then continue below to set up your new 365 account. The steps below describe how to set up your email account using Mac Mail on OS X 10.9 and above. If you are setting up your device or if you have recently changed your password, you may configure your device using the settings below.

How to set up email on mac