Outlook : Selecting Multiple Messages
You may want to delete multiple messages or move multiple messages in one go. To do this you can select multiple messages and perform an action on all of them.
To select multiple messages, first select the first message you wish to select using the left mouse button. Then, use hold down shift and click the left mouse mutton on the last message you wish to select:
You can now right click all the messages and choose and action to perform on all messages.