Multi-line layout is only available in a table view type.
On the View menu, point to Arrange By, and then click Custom.
Click Other Settings.
Under Other Options, do one of the following:
To always use multi-line layout, select Always use multi-line layout.
If this option is unavailable, clear the Use multi-line layout in widths smaller than n characters check box, and then select Always use multi-line layout.
To specify the width at which Microsoft Outlook switches to single-line layout to show more fields, select the Use multi-line layout in widths smaller than n characters check box, and then type the number you want for n.