How do i make my iPhone fit full screen in iMovie so I can burn it onto a dvd??

If you shot your video on the iPhone holding it in the portrait position, you will need to apply the zoom feature in iMovie to frame the shot. This will cause quite a reduction in video quality, however. For better results, always shoot video in landscape mode on the iPhone.

First drag the clip from an Event to an iMovie Project. Then you can use the Rotate, Crop, Ken Burns Tool that you will find on the middle toolbar.

FIT will fill the screen by letterboxing (black columns) so you will see the entire video.

CROP will fill the screen by chopping off the top and bottom.