Including an attachment with your message is easier than ever. Just as you've always done, you'll begin by creating a new message. Then you'll use the Attach File command on the Ribbon.
Use this command to attach documents or pictures to your message.
Where you'll find Attach File
Because including an attachment is such a common activity, Attach File is available from both the Message tab and the Insert tab. In the picture, we've shown it on the Insert tab.
You can't attach just anything
Outlook will block certain types of file attachments. Although this behavior is unchanged from earlier versions, you may be interested to know that some file types that were previously blocked are now allowed and some new types have been added to the blocked list.
To see a complete list of blocked file types and to read more about how to avoid having your attached files blocked, see the article Blocked attachments in Outlook.