Change the canvas size
The canvas displays a preview of the video at the location of the playhead on the timeline. For best results, adjust the canvas size to the dimensions you plan to export your final video to before editing.
Change the canvas dimensions
Select Edit > Adjust Canvas or click the canvas scale dropdown and select Adjust Canvas.
The Canvas controls appear under the canvas. Camtasia dims the entire application except for the canvas area. Enter the dimensions you plan to export your video (in pixels) into the Width and Height fields or select a common export from the Preset Menu.
Click Apply.
Tip: Set the canvas zoom scale to 100% to preview how the final video will appear exported at the current canvas dimensions.