I agree with Shane…
But if for some reason you do need to resize or stretch the video like for instance if your video is the wrong size due to mixing multiple formats in one sequence;
Then the easiest way is to double click on the video when it’s on the timeline and then select the ‘motion’ tab in the ‘viewer’ window. Then play with the ‘Basic motion’ (scale) and ‘distort’ tools (aspect ratio) until it looks the way you like.
Dan Soekov
Sydney Based Lighting Cameraman / Editor
https://danielsoekov.com