This article applies to: Outlook 2016 for Mac
To send a message, click E-mail in the Home ribbon.
A new message window will open.
You can either click the address book next to the To, Cc, or Bcc field to select names, or type email addresses in the desired field(s). After you've typed a few characters, Outlook will display a list of matches. Click a match to select it.
A single message can be addressed to no more than 300 individual addresses. That's the combined total of the To, Cc, and Bcc lines.
Sending on Behalf of Someone Else
You can only change the information in the From field if you have been given delegate rights for another person. Copies of the messages you send on their behalf will be stored in your own Sent Items folder, not theirs. See our Acting On Behalf Of article for more information.
Sending from a Resource or Exchange Group Account
(What are Resource and Exchange Group Accounts?)
You can only change the information in the From field if you have been given the necessary rights by an EGA Owner or Administrator. Copies of the messages you send on their behalf will be stored in your own Sent Items folder, not theirs.
After entering a Subject and completing the body of your message, click Send in the Message ribbon.
While composing a message, click on the paperclip in the Message ribbon.
Navigate to the file you want to attach, select it, and click Choose.
You can also drag a file from your desktop or folder into the new message window. The file name will appear in the Attachments field.
The maximum size of a message, including any attachments, is 25 megabytes. Encoding the attachment (making it part of the message) adds to its size, so if a file is almost 25 MB, it may be too large when encoded.