Click the folder whose content you want to sort.
Click the heading of the column by which you want to sort. For example, to sort by sender, click the From column header.
Messages are sorted by sender. To change the sort order from ascending to descending or vice versa, click the column heading (in this case, From) again.
Mail can quickly pile up in your mail folders, making it difficult to find a particular message. By default, Outlook lists messages in date order, but you can change how messages are sorted to suit your needs. For example, you can sort by subject or sender and in ascending or descending order.
Expanding and Collapsing Messages
To collapse a group of messages, displaying only the category or group name, click the minus sign (?) next to the message group. To expand the group to show all messages in that group, click the plus sign (+).