Click on the background and you can see the Zoom option in the upper toolbar.
Then, drag the slider to the left or right, or click the Fit or Fill button to zoom it directly. Finally, click the Done button to save this change.
You can apply the setting to all scenes.
When the size of your image/video does not match the canvas ratio, you can adjust the color of the black part or choose a Blur effect.
Tips: When it is greater than 100%, you can drag the image or video on the canvas to select the part you want to keep or highlight.
